Selective deposition of metals, metal oxides, and dielectrics

ABSTRACT

Methods are provided for selectively depositing a material on a first surface of a substrate relative to a second, different surface of the substrate. The selectively deposited material can be, for example, a metal, metal oxide, or dielectric material.

This application is a continuation of U.S. application Ser. No.14/612,784, filed Feb. 3, 2015, now U.S. Pat. No. 9,895,715, whichclaims priority to U.S. Provisional Application No. 61/935,798, filedFeb. 4, 2014, each of which is hereby incorporated by reference in itsentirety.

BACKGROUND OF THE INVENTION Field of the Invention

The present application relates to selective deposition on a firstsurface of a substrate relative to a second surface.

Description of the Related Art

Integrated circuits are currently manufactured by an elaborate processin which various layers of materials are sequentially constructed in apredetermined arrangement on a semiconductor substrate.

The predetermined arrangement of materials on a semiconductor substrateis often accomplished by deposition of a material over the entiresubstrate surface, followed by removal of the material frompredetermined areas of the substrate, such as by deposition of a masklayer and subsequent selective etching process.

In certain cases, the number of steps involved in manufacturing anintegrated surface on a substrate may be reduced by utilizing aselective deposition process, wherein a material is selectivelydeposited on a first surface relative to a second surface without theneed, or with reduced need for subsequent processing. Methods aredisclosed herein for selective deposition on a first surface ofsubstrate relative to a second, different surface of the substrate.

SUMMARY OF THE INVENTION

According to some aspects of the present disclosure, selectivedeposition can be used to deposit a material on a first surface of asubstrate relative to a second, different surface of a substrate. Insome embodiments atomic layer deposition (ALD) type processes are used.In some embodiments a metal is selectively deposited on a first surfaceof a substrate relative to a second different surface of a substrate. Insome embodiments a metal oxide is selectively deposited on a firstsurface of a substrate relative to a second different surface of asubstrate. In some embodiments a dielectric is selectively deposited ona first surface of a substrate relative to a second different surface ofa substrate.

In some embodiments the material is selectively deposited on the firstsurface relative to the second, different surface with a selectivity ofat least 90%. In some embodiments the selectivity is retained for up to20 deposition cycles.

In some embodiments a substrate comprising a first surface and a second,different surface is provided and a metal is selectively deposited onthe first surface relative to the second surface using an ALD typeprocess comprising a plurality of deposition cycles, each cyclecomprising alternately and sequentially contacting a substrate with avapor phase metal precursor and a vapor phase second reactant. In someembodiments the selectively deposited metal is selected from Sb and Ge.

In some embodiments the metal precursor comprises a Sb reactant havingthe formula SbX₃, where X is a halogen.

In some embodiments the first surface is a metal surface and the secondsurface comprises OH terminations and the metal is selectively depositedon the first surface relative to the second surface. In some embodimentsthe metal surface is a Ni, Co, Cu, Al, Ru, or another noble metalsurface. In some embodiments the second surface is a dielectric surface,such as SiO₂, GeO₂, or a low-k surface. In some embodiments the secondsurface is treated to provide OH termination. In some embodiments thesecond surface is deactivated.

In some embodiments a substrate comprising a first surface and a second,different surface is provided and a dielectric is selectively depositedon the first surface relative to the second surface using an ALD typeprocess comprising a plurality of deposition cycles, each cyclecomprising alternately and sequentially contacting a substrate with avapor phase first precursor and a vapor phase second reactant. In someembodiments the selectively deposited dielectric material is selectedfrom GeO₂, SiO₂ and MgO.

In some embodiments the first precursor comprises a Ge-alkylamine andthe second reactant is water. In some embodiments the first precursorcomprises an aminosilane precursor and the second reactant comprisesozone. In some embodiments the first precursor comprises Mg(Cp)₂ and thesecond reactant is selected from water, ozone and a combination of waterand ozone.

In some embodiments the first surface is a dielectric surface and thesecond surface is a metal surface. In some embodiments the first surfaceis a dielectric surface, such as SiO₂, GeO₂, or a low-k surface. In someembodiments the metal surface is treated to inhibit deposition of thedielectric material thereon prior to selective deposition. In someembodiments the metal surface is oxidized prior to selective deposition.In some embodiments the metal surface is passivated prior to selectivedeposition.

In some embodiments the first surface is a porous, low-k film. Theporous, low-k film may be present in a dual damascene structure, forexample. In some embodiments a dielectric is selectively deposited as apore sealing layer on the porous, low-k film. In some embodiments thedielectric material is GeO₂ or MgO. In some embodiments the pore sealinglayer is deposited on the low-k film without significantly increasingthe effective k value. In some embodiments the pore sealing layer sealspore of about 3 nm or less in diameter.

In some embodiments a substrate comprising a first surface and a second,different surface is provided and a metal or metal oxide is selectivelydeposited on the first surface relative to the second surface using anALD type process comprising a plurality of deposition cycles, each cyclecomprising alternately and sequentially contacting a substrate with avapor phase first precursor and a vapor phase second reactant. In someembodiments the selectively deposited material is selected from Ni, Fe,Co, NiOx, FeOx, and CoOx.

In some embodiments the first surface is a dielectric surface and thesecond surface is a metal surface. In some embodiments the secondsurface is a dielectric surface, such as SiO2, GeO2, or a low-k surface.In some embodiments the metal surface is treated to inhibit depositionof the dielectric material thereon prior to selective deposition. Insome embodiments the metal surface is oxidized prior to selectivedeposition. In some embodiments the metal surface is passivated prior toselective deposition.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood from the Detailed Descriptionand from the appended drawings, which are meant to illustrate and not tolimit the invention, and wherein:

FIG. 1 illustrates a deposition process flow for selectively depositinga material on a first surface of a substrate relative to a second,different surface of the same substrate.

FIG. 2 illustrates a deposition process flow for selectively depositingSb on a first surface of a substrate relative to a second, differentsurface of the same substrate.

FIG. 3 illustrates a deposition process flow for selectively depositingGe on a first surface of a substrate relative to a second, differentsurface of the same substrate.

FIG. 4 illustrates a deposition process flow for selectively depositingGeO₂ on a first surface of a substrate relative to a second, differentsurface of the same substrate.

FIG. 5 illustrates a deposition process flow for selectively depositingSiO₂ on a first surface of a substrate relative to a second, differentsurface of the same substrate.

FIG. 6 illustrates a deposition process flow for selectively depositingMgO on a first surface of a substrate relative to a second, differentsurface of the same substrate.

FIG. 7A illustrates a dual damascene structure after selectivedeposition of a pore sealing layer.

FIG. 7B is an enlarged view of the via sidewall of FIG. 7B shown incross-section, illustrating that the low k material comprises aplurality of pores within a matrix of insulating material.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

In some situations it is desirable to selectively deposit a material onone surface of a substrate relative to a second, different surface ofthe same substrate. For example, selective deposition may be used toform capping layers, barrier layers, etch stop layers, sacrificialand/or protective layers or for sealing pores, such as in porous low kmaterials. For example, a metallic material may be deposited selectivelyon a first metal surface of a substrate preferentially over a second,different surface, such as a dielectric surface of the same substrate.In other embodiments a dielectric material, such as an oxide, may bedeposited selectively on a first dielectric surface relative to a secondsurface, such as a conductive surface, metal surface, or H-terminatedsurface of the same substrate.

One or more surfaces may be treated in order to enhance deposition onone surface relative to one or more different surfaces. In someembodiments a first surface is treated, or activated, in order toenhance deposition on the first surface relative to a second surface. Insome embodiments a second surface is treated, or deactivated, in orderto decrease deposition on the second surface relative to a firstsurface. In some embodiments a first surface is treated to enhancedeposition and a second surface is treated to decrease deposition,thereby increasing selective deposition on the first surface relative tothe second surface. In some embodiments the deactivating treatment doesnot involve formation of a self-assembled monolayer (SAM) or a similarmonolayer having a long carbon chain. In some embodiments thedeactivating treatment is not treatment with an organic agent. Forexample, in some embodiments the deactivating treatment may be oxidationor halogenation, such as chlorination of the surface.

For example, in some embodiments a dielectric material is deposited on afirst dielectric surface of a substrate relative to a second metalsurface, and the second metal surface is oxidized prior to or at thebeginning of the dielectric material depositions in order to decreasedeposition of an oxide on the metal surface relative to the dielectricsurface. That is, selective deposition on the dielectric surface isincreased relative to the treated metal surface. In some embodiments themetal surface is passivated, such as by treating the surface such thatit comprises alkylsilyl groups. The passivation may facilitate selectivedeposition on the dielectric surface relative to the treated metalsurface. For example, deposition of an oxide on the metal surface may beinhibited by the passivation. In some embodiments passivation does notinclude formation of a single atomic monolayer (SAM) or a similarmonolayer having a long carbon chain on the metal surface. In someembodiments a dielectric surface may be treated to facilitate selectivedeposition of a metal on a metal surface relative to the dielectricsurface. For example, the dielectric surface may be treated to provide ahydrophilic OH-terminated surface. While an OH-terminated surface can bereactive to certain precursors, other precursors may not react with thistermination. For example, an OH-terminated surface can be passiveagainst Cu-amidinate compound adsorption or ruthenium compoundadsorption, which have two cyclopentadienyl (or a derivative thereof)ligands. Thus, in some embodiments OH-termination can be used to inhibitdeposition of a metal on a dielectric surface relative to a metalsurface.

The surface of dielectric materials such as SiO2 or GeO2 may comprisehydroxyl, or OH-groups which have the effect of making the surfacehydrophilic. Such OH-group surface terminations can occur naturally whenthe surface is exposed to ambient conditions. In some embodiments thedielectric surface may be treated to provide a hydrophilic OH-terminatedsurface. In some embodiments a hydrophilic OH-terminated surface may betreated to increase the amount of OH-groups on the surface. For example,the dielectric surface may be exposed to H₂O vapor in order to increasethe number of OH-groups at the surface. Another example includesexposing a dielectric surface to a carrier gas that has flowed through abubbler at a temperature of between 25 C and 40 C. In some embodimentsthe dielectric surface is exposed to air in order to provide ahydrophilic surface that comprises at least some OH-groups. In someembodiments a hydrophilic surface is not treated prior to deposition.

In some embodiments a dielectric surface can be passivated to inhibitdeposition of a metal thereon. For example, the dielectric surface maybe contacted with a chemical that provides a silylated (—Si—(CH₃)_(x) or—Si(CH₃)₃) surface or a halogenated surface or a —SiH₃ surface. In someembodiments the dielectric surface is chlorinated or fluorinated, suchas a Si—Cl surface. A halogenated surface can be achieved by treatingthe surface with a halide chemical, such as CCl₄ or a metal halide,which is capable of forming volatile metal oxyhalides, such as WF₆,NbF₅, or NbCl₅, and leaving the halide, such as the chloride or fluorideon the surface. The passivation can be used to inhibit deposition of ametal on the dielectric surface relative to a metal surface. In someembodiments the passivation chemical is one or more oftrimethylchlorosilane (CH₃)₃SiCl (TMCS), trimethyldimethylaminosilane(CH₃)₃SiN(CH₃)₂ or another type of alkyl substituted silane havingformula R_(4-x)SiX_(x), wherein x is from 1 to 3 and each R canindependently selected to be a C1-C5 hydrocarbon, such as methyl, ethyl,propyl or butyl, preferably methyl, and X is halide or X is anothergroup capable of reacting with OH-groups, such as an alkylamino group—NR₁R₂, wherein each R₁ can be independently selected to be hydrogen orC1-C5 hydrocarbon, preferably methyl or ethyl, R₂ can be independentlyselected to be C1-C5 hydrocarbon, preferably methyl or ethyl, preferablyX is chloride or dimethylamino. In some embodiments the passivationchemical can be a silane compound comprising at least one alkylaminogroup, such as bis(diethylamino)silane, or a silane compound comprisinga SiH₃ group, or silazane, such hexamethyldisilazane (HMDS).

In some embodiments a semiconductor substrate is provided that comprisesa first surface comprising a first material and a second surfacecomprising a second material that is different from the first material.In some embodiments the first surface is hydrophilic and may comprise anOH-terminated surface or a surface having some amount of OH-groups. Insome embodiments the first surface may be, for example and withoutlimitation, a low-k material, SiO₂ or GeO₂. In some embodiments thesecond surface is a metal surface. In some embodiments the secondsurface is a conductive surface. In some embodiments the second surfaceis a H-terminated surface. For example, the second surface may comprise,for example, Cu, Ni, Co, Al, Ru or another noble metal. For the purposesof the present application, Sb and Ge are considered to be metals. Insome embodiments the second surface comprises a metal selectedindividually from Cu, Ni, Co, Al, Ru and other noble metals. In someembodiments the second surface is a Cu surface. In some embodiments thesecond surface is a Ni surface. In some embodiments the second surfaceis a Co surface. In some embodiments the second surface is an Alsurface. In some embodiments the second surface is a Ru surface. In someembodiments the second surface comprises a noble metal. In someembodiments the conductive surface comprises an oxide such as CuOx,NiOx, CoOx or RuOx or another noble metal oxide. In some embodiments aconductive surface may no longer be conductive after it has beentreated. For example, a conductive surface may be treated prior to or atthe beginning of the selective deposition process, such as by oxidation,and the treated surface may no longer be conductive.

In some embodiments the deposition process is an atomic layer deposition(ALD) type process. In some embodiments the deposition process is a pureALD process. In some embodiments the deposition process is a vapordeposition process comprising one or more deposition cycles in which asubstrate is alternately and sequentially contacted with a first vaporphase reactant and a second vapor phase reactant.

In some embodiments, a Sb layer is selectively deposited on a firstmetal surface on a substrate relative to a second dielectric surface onthe same substrate. In some embodiments, prior to deposition of the Sblayer the second dielectric surface is treated with a passivationchemical to form a passivated surface, such as a silylated —Si—(CH₃)_(x)or —Si(CH₃)₃ surface or a H-terminated surface, such as a —SiH₃ surfaceor a halogenated surface, such as a chlorinated or fluorinated surface.As used herein a passivated surface is a surface that is passive againstdeposition of a certain material, or a surface that is passive withrespect to certain precursors used in a selective deposition process.For example, the halogenated surface may be a Si—Cl surface. In someembodiments the first metal surface may comprise, for example, Cu, Al,Ni, Co, Ru or another noble metal. In some embodiments the first metalsurface is oxygen terminated or an oxidized surface.

In some embodiments a Ge layer is selectively deposited on a first metalsurface of a substrate relative to a second dielectric surface on thesame substrate. In some embodiments the first surface may comprise, forexample, Cu, Al, Co, Ni, Ru or another noble metal.

In some embodiments, a GeO₂ layer is deposited on a first dielectricsurface of a substrate relative to a second surface of the samesubstrate, such as a conductive surface, metal surface, or H-terminatedsurface. In some embodiments the first surface may be, for example andwithout limitation, a low-k material, SiO₂ or GeO₂. The second surfacemay comprise, for example, Cu, Al, Ni, Co, Ru or another noble metal. Insome embodiments the conductive surface comprises an oxide such as CuOx,NiOx, CoOx or RuOx or another noble metal oxide. In some embodiments aconductive surface may no longer be conductive after it has beentreated. For example, a conductive surface may be treated prior to or atthe beginning of the selective deposition process, such as by oxidation,and the treated surface may no longer be conductive.

In some embodiments a SiO₂ layer is deposited on a first dielectricsurface of a substrate relative to a second surface of the samesubstrate, such as a conductive surface, metal surface, or H-terminatedsurface. In some embodiments the first surface may be, for example andwithout limitation, a low-k material, SiO₂ or GeO₂. The conductivesurface may comprise, for example, Cu, Al, Co, Ni, Ru or another noblemetal. In some embodiments the conductive surface comprises an oxidesuch as CuOx, NiOx, CoOx or RuOx or another noble metal oxide. In someembodiments a conductive surface may no longer be conductive after ithas been treated. For example, a conductive surface may be treated priorto or at the beginning of the selective deposition process, such as byoxidation, and the treated surface may no longer be conductive.

In some embodiments a MgO layer is deposited on a first dielectricsurface of a substrate relative to a second surface of the samesubstrate, such as a conductive surface, metal surface, or H-terminatedsurface. In some embodiments the first surface may be, for example andwithout limitation, a low-k material, SiO₂ or GeO₂. The conductivesurface may comprise, for example, Cu, Al, Co, Ni, Ru or another noblemetal. In some embodiments the conductive surface comprises an oxidesuch as CuOx, NiOx, CoOx or RuOx or another noble metal oxide. In someembodiments a conductive surface may no longer be conductive after ithas been treated. For example, a conductive surface may be treated priorto or at the beginning of the selective deposition process, such as byoxidation, and the treated surface may no longer be conductive.

In some embodiments the selective deposition processes disclosed hereindo not utilize plasma, such as direct plasma. In some instances,however, a selective deposition process could utilize radicals made byplasma as a reactant. The radicals are preferably not too energetic andthus do not destroy or degrade a surface of the substrate. Typicallydirect plasma can harm the second surface of the substrate toosignificantly to be useful, and thus is not used in some embodiments.

In some embodiments deposition on the first surface of the substraterelative to the second surface of the substrate is at least about 90%selective, at least about 95% selective, at least about 96%, 97%, 98% or99% or greater selective. In some embodiments deposition only occurs onthe first surface and does not occur on the second surface. In someembodiments deposition on the first surface of the substrate relative tothe second surface of the substrate is at least about 80% selective,which may be selective enough for some particular applications. In someembodiments the deposition on the first surface of the substraterelative to the second surface of the substrate is at least about 50%selective, which may be selective enough for some particularapplication.

In some embodiments an etch may be used subsequent to or in the courseof deposition to remove material that is non-selectively deposited.Although addition of an etch step would typically add cost andcomplexity to the process, in some situations it may be commerciallydesirable, for example if it is overall less expensive than otheroptions. In some embodiments the etch process may be a wet etch processor a dry etch process. In some embodiments a dry etch is preferable.

In some embodiments deposition on the first surface of the substraterelative to the second surface of the substrate can be performed up toabout 500 deposition cycles before losing the selectivity, or up toabout 50 deposition cycles, or up to about 20 deposition cycles, or upto about 10 deposition cycles, or up to about 5 deposition cycles beforelosing selectivity. In some embodiments even deposition of 1 or 2 cyclesbefore losing selectivity can be useful.

A loss of selectivity can be understood to have occurred when theselectivities mentioned above are no longer met. Depending on thespecific circumstances, a loss of selectivity may be considered to haveoccurred when deposition on the first surface of the substrate relativeto the second surface of the substrate is less than about 90% selective,less than about 95% selective, less than about 96%, 97%, 98% or 99%selective or greater.

In some embodiments deposition on the first surface of the substraterelative to the second surface of the substrate can be performed up to athickness of about 50 nm before losing the selectivity, or up to about10 nm, or up to about 5 nm, or up to about 3 nm, or up to about 2 nm, orup to about 1 nm before losing selectivity. In some embodiments evendeposition of up to 3 Å or 5 Å before losing selectivity can be useful.Depending on the specific circumstances, a loss of selectivity may beconsidered to have occurred when deposition on the first surface of thesubstrate relative to the second surface of the substrate is less thanabout 90% selective, less than about 95% selective, less than about 96%,97%, 98% or 99% selective or greater.

ALD Type Processes

ALD type processes are based on controlled, self-limiting surfacereactions of precursor chemicals. Gas phase reactions are avoided byalternately and sequentially contacting the substrate with theprecursors. Vapor phase reactants are separated from each other on thesubstrate surface, for example, by removing excess reactants and/orreactant byproducts from the reaction chamber between reactant pulses.

Briefly, a substrate comprising a first surface and second, differentsurface is heated to a suitable deposition temperature, generally atlowered pressure. Deposition temperatures are generally maintained belowthe thermal decomposition temperature of the reactants but at a highenough level to avoid condensation of reactants and to provide theactivation energy for the desired surface reactions. Of course, theappropriate temperature window for any given ALD reaction will dependupon the surface termination and reactant species involved. Here, thetemperature varies depending on the type of film being deposited and ispreferably at or below about 400° C., more preferably at or below about200° C. and most preferably from about 20° C. to about 200° C.

The surface of the substrate is contacted with a vapor phase firstreactant. In some embodiments a pulse of vapor phase first reactant isprovided to a reaction space containing the substrate. In someembodiments the substrate is moved to a reaction space containing vaporphase first reactant. Conditions are preferably selected such that nomore than about one monolayer of the first reactant is adsorbed on thesubstrate surface in a self-limiting manner. The appropriate contactingtimes can be readily determined by the skilled artisan based on theparticular circumstances. Excess first reactant and reaction byproducts,if any, are removed from the substrate surface, such as by purging withan inert gas or by removing the substrate from the presence of the firstreactant.

Purging means that vapor phase precursors and/or vapor phase byproductsare removed from the substrate surface such as by evacuating a chamberwith a vacuum pump and/or by replacing the gas inside a reactor with aninert gas such as argon or nitrogen. Typical purging times are fromabout 0.05 to 20 seconds, more preferably between about 1 and 10, andstill more preferably between about 1 and 2 seconds. However, otherpurge times can be utilized if necessary, such as where highly conformalstep coverage over extremely high aspect ratio structures or otherstructures with complex surface morphology is needed.

The surface of the substrate is contacted with a vapor phase secondgaseous reactant. In some embodiments a pulse of a second gaseousreactant is provided to a reaction space containing the substrate. Insome embodiments the substrate is moved to a reaction space containingthe vapor phase second reactant. Excess second reactant and gaseousbyproducts of the surface reaction, if any, are removed from thesubstrate surface. The steps of contacting and removing are repeateduntil a thin film of the desired thickness has been selectively formedon the first surface of substrate, with each cycle leaving no more thana molecular monolayer. Additional phases comprising alternately andsequentially contacting the surface of a substrate with other reactantscan be included to form more complicated materials, such as ternarymaterials.

As mentioned above, each phase of each cycle is preferablyself-limiting. An excess of reactant precursors is supplied in eachphase to saturate the susceptible structure surfaces. Surface saturationensures reactant occupation of all available reactive sites (subject,for example, to physical size or “steric hindrance” restraints) and thusensures excellent step coverage. Typically, less than one molecularlayer of material is deposited with each cycle, however, in someembodiments more than one molecular layer is deposited during the cycle.

Removing excess reactants can include evacuating some of the contents ofa reaction space and/or purging a reaction space with helium, nitrogenor another inert gas. In some embodiments purging can comprise turningoff the flow of the reactive gas while continuing to flow an inertcarrier gas to the reaction space.

The precursors employed in the ALD type processes may be solid, liquidor gaseous materials under standard conditions (room temperature andatmospheric pressure), provided that the precursors are in vapor phasebefore they are contacted with the substrate surface. Contacting asubstrate surface with a vaporized precursor means that the precursorvapor is in contact with the substrate surface for a limited period oftime. Typically, the contacting time is from about 0.05 to 10 seconds.However, depending on the substrate type and its surface area, thecontacting time may be even higher than 10 seconds. contacting times canbe on the order of minutes in some cases. The optimum contacting timecan be determined by the skilled artisan based on the particularcircumstances.

The mass flow rate of the precursors can also be determined by theskilled artisan. In some embodiments the flow rate of metal precursorsis preferably between about 1 and 1000 sccm without limitation, morepreferably between about 100 and 500 sccm.

The pressure in a reaction chamber is typically from about 0.01 to about20 mbar, more preferably from about 1 to about 10 mbar. However, in somecases the pressure will be higher or lower than this range, as can bedetermined by the skilled artisan given the particular circumstances.

Before starting the deposition of the film, the substrate is typicallyheated to a suitable growth temperature. The growth temperature variesdepending on the type of thin film formed, physical properties of theprecursors, etc. The growth temperatures are discussed in greater detailbelow in reference to each type of thin film formed. The growthtemperature can be less than the crystallization temperature for thedeposited materials such that an amorphous thin film is formed or it canbe above the crystallization temperature such that a crystalline thinfilm is formed. The preferred deposition temperature may vary dependingon a number of factors such as, and without limitation, the reactantprecursors, the pressure, flow rate, the arrangement of the reactor,crystallization temperature of the deposited thin film, and thecomposition of the substrate including the nature of the material to bedeposited on. The specific growth temperature may be selected by theskilled artisan.

Examples of suitable reactors that may be used include commerciallyavailable ALD equipment such as the F-120® reactor, Pulsar® reactor andAdvance® 400 Series reactor, available from ASM America, Inc of Phoenix,Ariz. and ASM Europe B.V., Almere, Netherlands. In addition to these ALDreactors, many other kinds of reactors capable of ALD growth of thinfilms, including CVD reactors equipped with appropriate equipment andmeans for pulsing the precursors can be employed. In some embodiments aflow type ALD reactor is used. Preferably, reactants are kept separateuntil reaching the reaction chamber, such that shared lines for theprecursors are minimized. However, other arrangements are possible, suchas the use of a pre-reaction chamber as described in U.S. patentapplication Ser. No. 10/929,348, filed Aug. 30, 2004 and Ser. No.09/836,674, filed Apr. 16, 2001, the disclosures of which areincorporated herein by reference.

The growth processes can optionally be carried out in a reactor orreaction space connected to a cluster tool. In a cluster tool, becauseeach reaction space is dedicated to one type of process, the temperatureof the reaction space in each module can be kept constant, whichimproves the throughput compared to a reactor in which is the substrateis heated up to the process temperature before each run.

A stand-alone reactor can be equipped with a load-lock. In that case, itis not necessary to cool down the reaction space between each run.

Referring to FIG. 1 and according to some embodiments a substratecomprising a first surface and a second surface is provided at step 110and a material is selectively deposited on a first surface of thesubstrate relative to a second surface by an ALD type deposition process100 comprising multiple cycles, each cycle comprising:

contacting the surface of a substrate with a vaporized first precursorat step 130;

removing excess first precursor and reaction by products, if any, fromthe surface at step 140;

contacting the surface of the substrate with a second vaporized reactantat step 150;

removing from the surface, at step 160, excess second reactant and anygaseous by-products formed in the reaction between the first precursorlayer on the first surface of the substrate and the second reactant,and;

repeating at step 170 the contacting and removing steps until a thinfilm comprising the selectively deposited material of the desiredthickness has been formed.

As mentioned above, in some embodiments one or more surfaces of thesubstrate may be treated in order to enhance deposition on one surfacerelative to one or more different surfaces prior to beginning thedeposition process 100. In FIG. 1 this is indicated by step 120.

Although the illustrated deposition cycle begins with contacting thesurface of the substrate with the first precursor, in other embodimentsthe deposition cycle begins with contacting the surface of the substratewith the second reactant. It will be understood by the skilled artisanthat contacting the substrate surface with the first precursor andsecond reactant are interchangeable in the ALD cycle.

In some embodiments, the reactants and reaction by-products can beremoved from the substrate surface by stopping the flow of firstprecursor while continuing the flow of an inert carrier gas such asnitrogen or argon.

In some embodiments, the reactants and reaction by-products can beremoved from the substrate surface by stopping the flow of secondreactant while continuing the flow of an inert carrier gas. In someembodiments the substrate is moved such that different reactantsalternately and sequentially contact the surface of the substrate in adesired sequence for a desired time. In some embodiments the removingsteps, 140 and 160 are not performed. In some embodiments no reactantmay be removed from the various parts of a chamber. In some embodimentsthe substrate is moved from a part of the chamber containing a firstprecursor to another part of the chamber containing the second reactant.In some embodiments the substrate is moved from a first reaction chamberto a second, different reaction chamber.

Selective Deposition of Metal on Metal

As mentioned above, in some embodiments a metal is selectively depositedon a first metal surface of a substrate relative to a second, differentsurface, such as a dielectric surface of the same substrate. In someembodiments the first metal surface is a noble metal surface. In someembodiments the first metal surface is an Al, Cu, Ru, Ni, Co, or othernoble metal surface. In some embodiments the first surface comprises ametal selected individually from Cu, Ni, Co, Al, Ru and other noblemetals. In some embodiments the first surface is a Cu surface. In someembodiments the first surface is a Ni surface. In some embodiments thefirst surface is a Co surface. In some embodiments the first surface isan Al surface. In some embodiments the first surface is a Ru surface. Insome embodiments the first surface comprises a noble metal. In someembodiments the second, non-metal surface, is a hydrophilic,OH-terminated surface or contains some amount of OH-groups. In someembodiments the second surface is a —NH, terminated surface. In someembodiments the second surface is a —SH, terminated surface. In someembodiments the second, non-metal, surface is a dielectric surface. Insome embodiments the second, non-metal surface is SiO2, GeO2, or low-kmaterial.

In some embodiments the second, non-metal surface is deactivated, suchas by a treatment to provide a surface on which metal deposition isinhibited. In some embodiments deactivation may comprise treatment witha passivation chemical. In some embodiments the deactivation treatmentcan occur prior to the deposition of a metal on a first metal surface.In some embodiments the deactivation treatment may be an in situdeactivation treatment. In some embodiments deactivation of thehydrophilic surface may comprise replacing at least OH-groups with othergroups. In some embodiments deactivation can include treatment toincrease the amount of OH-groups on the second, non-metal, surface.

In some embodiments the second surface is deactivated, such as bypassivation prior to deposition of a metal. In some embodimentsdeactivation of the second surface may comprise replacing at least someOH-groups with other groups. In some embodiments the second surface istreated with a passivation chemical to form a passivated surface. Forexample, the second surface may be silylated or halogenated, such aschlorinated or fluorinated, prior to deposition of the metal. In someembodiments the second surface may be treated to form a silylatedsurface, such as a silylated —Si—(CH₃)_(x) or —Si(CH₃)₃ surface. In someembodiments the second surface may be treated to form a halogenatedsurface, such as a chlorinated or fluorinated surface. For example, thehalogenated surface may be a Si—Cl surface. In some embodiments thesecond surface may be treated to provide a H-terminated surface, forexample a —SiH₃ surface. For example, in some embodiments the secondsurface may be contacted with a chemical that provides a —SiH₃ surface.

In some embodiments deposition on the first surface of the substraterelative to the second surface of the substrate is at least about 90%selective, at least about 95% selective, at least about 96%, 97%, 98% or99% or greater selective. In some embodiments deposition only occurs onthe first surface and does not occur on the second surface. In someembodiments deposition on the first surface of the substrate relative tothe second surface of the substrate is at least about 80% selective,which may be selective enough for some particular applications. In someembodiments deposition on the first surface of the substrate relative tothe second surface of the substrate is at least about 50% selective,which may be selective enough for some particular applications.

Selective Deposition of Sb on Metal by ALD

In some embodiments Sb is selectively deposited on a metal surface of asubstrate comprising a metal surface and a dielectric surface. In someembodiments, Sb is selectively deposited on a metal surface of asubstrate, such as a Cu, Ni, Co, Al, Ru, or other noble metal surface,relative to a hydrophilic surface of the same substrate. In someembodiments Sb is selectively deposited on a Cu surface, relative to asecond, different surface. In some embodiments Sb is selectivelydeposited on a Ni surface, relative to a second, different—surface. Insome embodiments Sb is selectively deposited on a Co surface, relativeto a second, different surface. In some embodiments Sb is selectivelydeposited on a Al surface, relative to a second, different surface. Insome embodiments Sb is selectively deposited on a Ru surface, relativeto a second, different surface. In some embodiments Sb is selectivelydeposited on a noble metal surface, relative to a second, differentsurface.

In some embodiments the second surface is a hydrophilic surface. In someembodiments the hydrophilic surface may comprise at least someOH-groups. In some embodiments the second surface is a —NH_(x)terminated surface. In some embodiments the second surface is a —SH_(x)terminated surface. In some embodiments the hydrophilic surface is adielectric surface. In some embodiments the hydrophilic surface maycomprise SiO₂, a low k material, or GeO₂.

As previously discussed, in some embodiments the second, hydrophilicsurface is treated to facilitate selective deposition of Sb on a metalsurface relative to the hydrophilic surface. For example, the secondsurface may be treated to provide a hydrophilic OH-terminated surface.In some embodiments a hydrophilic OH-terminated surface may be treatedto increase the amount of OH-groups on the surface. For example, thedielectric surface may be exposed to H₂O vapor in order to increase thenumber of OH-groups at the surface. Another example includes exposing adielectric surface to a carrier gas that has flowed through a bubbler ata temperature of between 25° C. and 40° C. In some embodiments thedielectric surface is exposed to air in order to provide a hydrophilicsurface that comprises at least some OH-groups. In some embodiments ahydrophilic surface is not treated prior to deposition.

In some embodiments the hydrophilic surface is deactivated, such as bypassivation prior to deposition of Sb. In some embodiments deactivationof the hydrophilic surface may comprise replacing at least OH-groupswith other groups. In some embodiments the hydrophilic dielectricsurface is treated with a passivation chemical to form a passivatedsurface. For example, the hydrophilic surface may be silylated orhalogenated, such as chlorinated or fluorinated, prior to deposition ofthe Sb. In some embodiments the hydrophilic surface may be treated toform a silylated surface, such as a silylated —Si—(CH₃)_(x) or —Si(CH₃)₃surface. In some embodiments the hydrophilic surface may be treated toform a halogenated surface, such as a chlorinated or fluorinatedsurface. For example, the halogenated surface may be a Si—Cl surface. Insome embodiments the hydrophilic surface may be treated to provide aH-terminated surface, for example a —SiH₃ surface. For example, in someembodiments the hydrophilic surface may be contacted with a chemicalthat provides a H-terminated surface. In some embodiments thehydrophilic surface may be contacted with HF to provide a H-terminatedsurface.

In some embodiments the passivation chemical is one or more oftrimethylchlorosilane (CH₃)₃SiCl (TMCS), trimethyldimethylaminosilane(CH₃)₃SiN(CH₃)₂ or another type of alkyl substituted silane havingformula R_(4-x)SiX_(x), wherein x is from 1 to 3 and each R canindependently selected to be a C1-C5 hydrocarbon, such as methyl, ethyl,propyl or butyl, preferably methyl, and X is halide or X is anothergroup capable of reacting with OH-groups, such as an alkylamino group—NR₁R₂, wherein each R₁ can be independently selected to be hydrogen orC1-C5 hydrocarbon, preferably methyl or ethyl, R₂ can be independentlyselected to be C1-C5 hydrocarbon, preferably methyl or ethyl, preferablyX is chloride or dimethylamino. In some embodiments the passivationchemical can be a silane compound comprising at least one alkylaminogroup, such as bis(diethylamino)silane, or a silane compound comprisinga SiH₃ group, or silazane, such hexamethyldisilazane (HMDS).

In some embodiments Sb deposition on the first surface of the substraterelative to the second surface of the substrate is at least about 90%selective, at least about 95% selective, at least about 96%, 97%, 98% or99% or greater selective. In some embodiments Sb deposition only occurson the first surface and does not occur on the second surface. In someembodiments Sb deposition on the first surface of the substrate relativeto the second surface of the substrate is at least about 80% selective,which may be selective enough for some particular applications. In someembodiments deposition on the first surface of the substrate relative tothe second surface of the substrate is at least about 50% selective,which may be selective enough for some particular applications.

In some embodiments Sb is selectively deposited by an ALD type process.In some embodiments Sb is selectively deposited without the use ofplasma. In some embodiments deposition may be carried out, for example,as described in U.S. Publication No. 2002/0329208 (U.S. application Ser.No. 13/504,079), which is hereby incorporated by reference.

Referring to FIG. 2 and according to a preferred embodiment a substratecomprising a first surface and a second surface is provided at step 210and a metal, here Sb, is selectively deposited on a first surface of asubstrate by an ALD type deposition process 100 comprising multiplecycles, each cycle comprising:

contacting the surface of a substrate with a vaporized first metalprecursor, here SbCl₃, at step 230;

removing excess metal precursor and reaction by products, if any, fromthe surface at step 240;

contacting the surface of the substrate with a second vaporizedreactant, here Sb(SiEt₃)₃, at step 250;

removing from the surface, at step 260, excess second reactant and anygaseous by-products formed in the reaction between the metal precursorlayer on the first surface of the substrate and the second reactant,and;

repeating at step 270 the contacting and removing steps until a metal,here Sb, thin film of the desired thickness has been formed.

As mentioned above, in some embodiments one or more surfaces of thesubstrate may be treated in order to enhance deposition on one surfacerelative to one or more different surfaces prior to beginning thedeposition process 200. In FIG. 2 this is indicated by step 220 in whichthe second, non-metal surface can be treated to provide an OH-terminatedsurface, or can be deactivated, such as by passivation, prior todeposition of the metal, here Sb.

Although the illustrated Sb deposition cycle begins with contacting thesurface of the substrate with the first Sb precursor, in otherembodiments the deposition cycle begins with contacting the surface ofthe substrate with the second reactant. It will be understood by theskilled artisan that contacting the substrate surface with the first Sbprecursor and second reactant are interchangeable in the ALD cycle.

In some embodiments, the reactants and reaction by-products can beremoved from the substrate surface by stopping the flow of the firstprecursor while continuing the flow of an inert carrier gas such asnitrogen or argon.

In some embodiments, the reactants and reaction by-products can beremoved from the substrate surface by stopping the flow of secondreactant while continuing the flow of an inert carrier gas such asnitrogen or argon.

In some embodiments the substrate is moved such that different reactantsalternately and sequentially contact the surface of the substrate in adesired sequence for a desired time. In some embodiments the removingsteps, 140 and 160 are not performed. In some embodiments no reactantmay be removed from the various parts of a chamber. In some embodimentsthe substrate is moved from a part of the chamber containing a firstprecursor to another part of the chamber containing the second reactant.In some embodiments the substrate is moved from a first reaction chamberto a second, different reaction chamber.

In some embodiments the second reactant can comprise a Sb precursor. Insome embodiments the second reactant is a second Sb precursor. In someembodiments the second reactant is a second Sb precursor that isdifferent from the first Sb precursor.

In some embodiments the first Sb precursor has a formula of SbX3,wherein X is a halogen element. In some embodiments the first Sbprecursor is SbCl3, SbBr3 or SbI3.

In some embodiments, the second reactant is not an oxygen source. Theterm “oxygen source” refers to reactants that comprise oxygen, such aswater, ozone, alcohol, oxygen atoms, oxygen plasma and oxygen radicals,typically used in ALD for depositing metal oxides. In some embodimentsthe second reactant is not water, ozone or alcohol.

In some embodiments the second reactant to be used in combination withthe Sb precursors disclosed herein is not an aminogermanium precursor,such as tetraminogermanium or organotellurium precursor. In someembodiments the second reactant to be used in combination with the Sbprecursors disclosed herein is not a chalcogenide precursor. In someembodiments the second reactant to be used in combination with the Sbprecursors disclosed herein does not contain plasma or an excitedspecies. In some embodiments the second reactant to be used incombination with the Sb precursors disclosed herein does not containnitrogen. In some embodiments the second reactant to be used incombination with the Sb precursors disclosed herein is not an alkoxidesubstituted precursor. In some embodiments the second reactant to beused in combination with the Sb precursors disclosed herein is not anamino substituted precursor. In some embodiments the second reactant tobe used in combination with the Sb precursors disclosed herein is not analkyl substituted precursor. In some embodiments the second reactant tobe used in combination with the Sb precursors disclosed herein does notcontain a direct Sb—C bond.

The Sb center atoms of the Sb precursors disclosed herein can be bondedto Si, Ge, or Sn atoms. Sb is more electronegative than Si, Ge or Sn,which will create polarity in bonds and thus a partial negative chargeon the Sb center atoms of the Sb precursors disclosed herein. In someembodiments, the Sb center atoms can have a negative oxidation state. Itis believed, although not being bound to any theory, that the slightpartial negative charge of the center atom in the precursors disclosedherein, for example the slight partial negative charge of Sb inSb(SiEt3)3, combined with the partial positive charge of the center atomin the other precursor, for example the partial positive charge of Sb inSbCl3, makes the precursor combination successful and film depositionpossible.

In some embodiments the second reactant to be used in combination withthe Sb precursors disclosed herein is not a reducing agent, such ashydrogen, H2/plasma, amine, imine, hydrazine, silane, silylchalcogenide, germane, ammonia, alkane, alkene or alkyne. As used hereina reducing agent refers to a compound capable of reducing an atom of theother reactant, usually the atom which will be deposited in the film inan ALD process and sometimes to elemental form. At the same time thereducing agent can be oxidized. It may be noted that with oxidativechemistry, for example with an oxidation agent, it is also possible toproduce elemental films if the formal oxidation states of the atom,which will be deposited, are negative in the other precursor. In someembodiments the Sb precursors disclosed herein act as a reducing agentin an ALD process.

In some embodiments the second reactant to be used in combination withSb precursors disclosed herein is an oxidizing precursor, such as SbCl3.Preferably the oxidizing precursor is not water, alcohol or ozone. Asused herein an oxidizing precursor is a precursor, which has a partialpositive charge in the center atom of the molecule, such as Sb in caseof SbCl3, and thus center atoms can be considered to have positiveoxidation states. The partial positive charge of the oxidizingprecursors will be decreased in the deposited film i.e. the center atomof the molecule can be considered to be somewhat reduced although noreal oxidation state increase has happened. In some embodiments theantimony deposition cycle only uses two reactive compounds.

Preferably, the second reactant is a Sb precursor with a formula ofSb(SiR1R2R3)3, wherein R1, R2, and R3 are alkyl groups comprising one ormore carbon atoms. The R1, R2, and R3 alkyl groups can be selected basedon the desired physical properties of the precursor such as volatility,vapor pressure, toxicity, etc

In some embodiments the first Sb precursor is SbCl3 and the second Sbprecursor is Sb(SiEt3)3.

The substrate temperature during selective Sb thin film deposition ispreferably less than 250° C. and more preferably less than 200° C. andeven more preferably below 150° C.

Pressure of the reactor can vary much depending from the reactor usedfor the depositions. Typically reactor pressures are below normalambient pressure.

The skilled artisan can determine the optimal reactant evaporationtemperatures based on the properties of the selected precursors. Theevaporation temperatures for the second Sb precursor, such asSb(SiEt3)3, which can be synthesized by the methods described herein, istypically about 85° C. The evaporation temperature for the first Sbprecursor, such as SbCl3, is typically about 30° C. to 35° C.

The skilled artisan can determine the optimal reactant contact timesthrough routine experimentation based on the properties of the selectedprecursors and the desired properties of the deposited Sb thin film.Preferably the first and second Sb reactants are contacted for about0.05 to 10 seconds, more preferably about 0.2 to 4 seconds, and mostpreferably about 1 to 2 seconds. The removal steps in which excessreactant and reaction by-products, if any, are removed are preferablyabout 0.05 to 10 seconds, more preferably about 0.2-4 seconds, and mostpreferably 1 to 2 seconds in length.

The growth rate of the elemental Sb thin films will vary depending onthe reaction conditions. As described below, in initial experiments, thegrowth rate varied between about 0.3 and about 0.5 Å/cycle.

As previously discussed, in some embodiments Sb deposition on the firstsurface of the substrate relative to the second surface of the substrateis at least about 90% selective, at least about 95% selective, at leastabout 96%, 97%, 98% or 99% or greater selective. In some embodiments Sbdeposition only occurs on the first surface and does not occur on thesecond surface. In some embodiments Sb deposition on the first surfaceof the substrate relative to the second surface of the substrate is atleast about 80% selective, which may be selective enough for someparticular applications. In some embodiments deposition on the firstsurface of the substrate relative to the second surface of the substrateis at least about 50% selective, which may be selective enough for someparticular applications.

Sb Precursors

Precursors that may be used as a first or second reactant in ALD typeselective deposition processes for Sb disclosed herein are discussedbelow.

In some embodiments the Sb precursors disclosed herein can be the firstSb precursor. In some embodiments the Sb precursors disclosed herein canbe the second reactant. In some embodiments the Sb precursors disclosedherein can be the first Sb precursor or the second reactant. In someembodiments the Sb precursors disclosed herein can be the first Sbprecursor and the second reactant. In some embodiments the first Sbprecursor is a Sb precursor disclosed herein and the second reactant isa second, different Sb precursor disclosed herein.

In some embodiments Sb precursors that may be used as the first Sbprecursor, the second reactant, or both include, Sb halides, such asSbCl₃ and SbI₃, Sb alkoxides, such as Sb(OEt)₃ and Sb amides.

In some embodiments a Sb precursor has Sb bound to at least one siliconatom, preferably at least to two silicon atoms and more preferably Sb isbound to three silicon atoms. For example it can have a general formulaof Sb(AR1R2R3)₃, wherein A is Si or Ge, and R1, R2, and R3 are alkylgroups comprising one or more carbon atoms. Each of the R1, R2 and R3ligands can be selected independently of each other. The R1, R2, and R3alkyl groups can be selected independently of each other in each ligandbased on the desired physical properties of the precursor such asvolatility, vapor pressure, toxicity, etc. In some embodiments, R1, R2and/or R3 can be hydrogen, alkenyl, alkynyl or aryl groups. In someembodiments, R1, R2, R3 can be any organic groups containingheteroatoms, such as N, O, F, Si, P, S, Cl, Br or I. In some embodimentsR1, R2, R3 can be halogen atoms. In some embodiments the Sb precursorhave a general formula of Sb(SiR1R2R3)₃, wherein R1, R2, and R3 arealkyl groups comprising one or more carbon atoms. In some embodiments,R1, R2 and/or R3 can be unsubstituted or substituted C1-C2 alkyls, suchas methyl or ethyl groups. The R1, R2, and R3 alkyl groups can beselected independently of each other in each ligand based on the desiredphysical properties of the precursor such as volatility, vapor pressure,toxicity, etc In some embodiments the Sb precursor is Sb(SiMe₂tBu)₃. Inother embodiments the precursor is Sb(SiEt₃)₃ or Sb(SiMe₃)₃. In morepreferred embodiments the precursor has a Sb—Si bond and most preferablya three Si—Sb bond structure.

In some embodiments a Sb precursor has a general formula ofSb[Al(X1R1R2R3)₃][A2(X2R4R5R6)₃][A3(X3R7R8R9)₃] wherein A1, A2, A3 canbe independently selected to be Si or Ge and wherein R1, R2, R3, R4, R5,R6, R7, R8, and R9, can be independently selected to be alkyl, hydrogen,alkenyl, alkynyl or aryl groups. In some embodiments, R1, R2, R3, R4,R5, R6, R7, R8, and R9 can be any organic groups containing alsoheteroatoms, such as N, O, F, Si, P, S, Cl, Br or I. In some embodimentsone or more R1, R2, R3, R4, R5, R6, R7, R8, and R9 can be halogen atoms.In some embodiments X1, X2, and X3 can be Si, Ge, N, or O. In someembodiments X1, X2, and X3 are different elements. In embodiments when Xis Si then Si will be bound to three R groups, for exampleSb[Si(SiR1R2R3)₃][Si(SiR4R5R6)₃][Si(SiR7R8R9)₃]. In embodiments when Xis N then nitrogen will only be bound to two R groupsSb[Si(NR1R2)3][Si(NR3R4)3][Si(NR5R6)3]. In embodiments when X is O, theoxygen will only be bound to one R group, for exampleSb[Si(OR1)₃][Si(OR2)₃][Si(OR3)₃]. R1, R2, R3, R4, R5, R6, R7, R8, and R9groups can be selected independently of each other in each ligand basedon the desired physical properties of the precursor such as volatility,vapor pressure, toxicity, etc.

Selective Deposition of Ge on Metal

In some embodiments Ge is selectively deposited on a metal surface, suchas Ni, Co, Cu, Al, Ru, or other noble metal relative to a hydrophilicsurface of the same substrate, such as a passivated surface. In someembodiments Ge is selectively deposited on a Cu surface, relative to asecond, different surface. In some embodiments Ge is selectivelydeposited on a Ni surface, relative to a second, different—surface. Insome embodiments Ge is selectively deposited on a Co surface, relativeto a second, different surface. In some embodiments Ge is selectivelydeposited on a Al surface, relative to a second, different surface. Insome embodiments Ge is selectively deposited on a Ru surface, relativeto a second, different surface. In some embodiments Ge is selectivelydeposited on a noble metal surface, relative to a second, differentsurface.

In some embodiments Ge is selectively deposited by a process such asthat described in U.S. application Ser. No. 14/135,383, filed Dec. 19,2013, which is hereby incorporated by reference.

In some embodiments Ge deposition on the first surface of the substraterelative to the second surface of the substrate is at least about 90%selective, at least about 95% selective, at least about 96%, 97%, 98% or99% or greater selective. In some embodiments Ge deposition only occurson the first surface and does not occur on the second surface. In someembodiments Ge deposition on the first surface of the substrate relativeto the second surface of the substrate is at least about 80% selective,which may be selective enough for some particular applications. In someembodiments deposition on the first surface of the substrate relative tothe second surface of the substrate is at least about 50% selective,which may be selective enough for some particular applications.

In some embodiments the second surface is a hydrophilic surface. In someembodiments the hydrophilic surface may comprise at least someOH-groups. In some embodiments the second surface is a —NH_(x)terminated surface. In some embodiments the second surface is a —SH_(x)terminated surface. In some embodiments the hydrophilic surface is adielectric surface. In some embodiments the hydrophilic surface maycomprise SiO₂, a low k material, or GeO₂. In some embodiments Ge isselectively deposited by an ALD type deposition process. For example,the substrate may be alternately and sequentially contacted with agermanium reactant, such as a germanium alkoxide or alkylamine and asecond reactant, such as a nitrogen reactant like NH₃.

As previously discussed, in some embodiments the second surface istreated to facilitate selective deposition of Ge on a metal surfacerelative to the second surface. For example, the second surface may betreated to provide a hydrophilic OH-terminated surface. In someembodiments a hydrophilic OH-terminated surface may be treated toincrease the amount of OH-groups on the surface. For example, thedielectric surface may be exposed to H₂O vapor in order to increase thenumber of OH-groups at the surface. Another example includes exposing adielectric surface to a carrier gas that has flowed through a bubbler ata temperature of between 25° C. and 40° C. In some embodiments thedielectric surface is exposed to air in order to provide a hydrophilicsurface that comprises at least some OH-groups. In some embodiments ahydrophilic surface is not treated prior to deposition.

In some embodiments the hydrophilic surface is deactivated, such as bypassivation prior to deposition of Ge. In some embodiments deactivationof the hydrophilic surface may comprise replacing at least OH-groupswith other groups. In some embodiments the hydrophilic dielectricsurface is treated with a passivation chemical to form a passivatedsurface. For example, the hydrophilic surface may be silylated orhalogenated, such as chlorinated or fluorinated, prior to deposition ofthe Sb. In some embodiments the hydrophilic surface may be treated toform a silylated surface, such as a silylated —Si—(CH₃)_(x) or —Si(CH₃)₃surface. In some embodiments the hydrophilic surface may be treated toform a halogenated surface, such as a chlorinated or fluorinatedsurface. For example, the halogenated surface may be a Si—Cl surface. Insome embodiments the hydrophilic surface may be treated to provide aH-terminated surface, for example a —SiH₃ surface. For example, in someembodiments the hydrophilic surface may be contacted with a chemicalthat provides a H-terminated surface.

As noted above, processes described herein enable use of ALD typedeposition techniques to selectively deposit germanium. The ALD typedeposition process is mostly surface-controlled (based on controlledreactions at the first substrate surface) and thus has the advantage ofproviding high conformality at relatively low temperatures. However, insome embodiments, the germanium precursor may at least partiallydecompose. Accordingly, in some embodiments the ALD type processdescribed herein is a pure ALD process in which no decomposition ofprecursors is observed. In other embodiments reaction conditions, suchas reaction temperature, are selected such that a pure ALD process isachieved and no precursor decomposition takes place.

Because of the variability in decomposition temperatures of differentcompounds, the actual reaction temperature in any given embodiment maybe selected based on the specifically chosen precursors. In someembodiments the deposition temperature is below about 600° C. In someembodiments the deposition temperature is below about 500° C. In someembodiments the deposition temperature is below about 450° C. In someembodiments the deposition temperature is preferably below about 400° C.and even, in some cases, below about 375° C.

In some embodiments Ge is selectively deposited on a first surface of asubstrate relative to a second, different surface of the substrate by anALD type process comprising alternately and sequentially contacting thesubstrate with a first Ge precursor and a second reactant.

Referring to FIG. 3 and according to a preferred embodiment a substratecomprising a first surface and a second surface is provided at step 310and a metal, here Ge, is selectively deposited on a first surface of asubstrate by an ALD type deposition process 300 comprising multiplecycles, each cycle comprising:

contacting the surface of a substrate with a vaporized first metalprecursor, here TDMAGe, at step 330;

removing excess metal precursor and reaction by products, if any, fromthe surface at step 340;

contacting the surface of the substrate with a second vaporizedreactant, here NH₃, at step 350;

removing from the surface, at step 360, excess second reactant and anygaseous by-products formed in the reaction between the metal precursorlayer on the first surface of the substrate and the second reactant,and;

repeating at step 370 the contacting and removing steps until a metal,here Ge, thin film of the desired thickness has been formed.

As mentioned above, in some embodiments one or more surfaces of thesubstrate may be treated in order to enhance deposition on one surfacerelative to one or more different surfaces prior to beginning thedeposition process 300. In FIG. 3 this is indicated by step 320 in whichthe second, non-metal surface can be treated to provide an OH-terminatedsurface, or can be deactivated, such as by passivation, prior todeposition of the metal, here Ge.

Although the illustrated Ge deposition cycle begins with contacting thesubstrate with the first Ge precursor, in other embodiments thedeposition cycle begins with contacting the substrate with the secondreactant. It will be understood by the skilled artisan that contactingthe substrate surface with the first Ge precursor and second reactantare interchangeable in the ALD cycle.

When the Ge precursor contacts the substrate, the Ge precursor may format least a monolayer, less than a monolayer, or more than a monolayer.

In some embodiments, a carrier gas is flowed continuously to a reactionspace throughout the deposition process. In some embodiments in eachdeposition cycle the first germanium precursor is pulsed into a reactionchamber. In some embodiments excess germanium precursor is then removedfrom the reaction chamber. In some embodiments, the carrier gascomprises nitrogen. In some embodiments a separate purge gas isutilized.

In some embodiments, the reactants and reaction by-products can beremoved from the substrate surface by stopping the flow of secondreactant while continuing the flow of an inert carrier gas. In someembodiments the substrate is moved such that different reactantsalternately and sequentially contact the surface of the substrate in adesired sequence for a desired time. In some embodiments the removingsteps, 140 and 160 are not performed. In some embodiments no reactantmay be removed from the various parts of a chamber. In some embodimentsthe substrate is moved from a part of the chamber containing a firstprecursor to another part of the chamber containing the second reactant.In some embodiments the substrate is moved from a first reaction chamberto a second, different reaction chamber.

The Ge precursor employed in the ALD type processes may be solid,liquid, or gaseous material under standard conditions (room temperatureand atmospheric pressure), provided that the Ge precursor is in vaporphase before it is contacted with the substrate surface.

Contacting a substrate surface with a vaporized precursor means that theprecursor vapor is in contact with the substrate surface for a limitedperiod of time. Typically, the contacting time is from about 0.05 to 10seconds. However, depending on the substrate type and its surface area,the contacting time may be even higher than 10 seconds. contacting timescan be on the order of minutes in some cases. The optimum contactingtime can be determined by the skilled artisan based on the particularcircumstances. In some embodiments the substrate is moved such thatdifferent reactants alternately and sequentially contact the surface ofthe substrate in a desired sequence for a desired time. In someembodiments the substrate is moved from a first reaction chamber to asecond, different reaction chamber. In some embodiments the substrate ismoved within a first reaction chamber.

In some embodiments, for example for a 300 mm wafer in a single waferreactor, the surface of a substrate is contacted with Ge precursor forfrom about 0.05 seconds to about 10 seconds, for from about 0.1 secondsto about 5 seconds or from about 0.3 seconds to about 3.0 seconds.

The surface of the substrate may be contacted with a second reactant forfrom about 0.05 seconds to about 10 seconds, from about 0.1 seconds toabout 5 seconds, or for from about 0.2 seconds to about 3.0 seconds.However, contacting times for one or both reactants can be on the orderof minutes in some cases. The optimum contacting time for each reactantcan be determined by the skilled artisan based on the particularcircumstances.

As mentioned above, in some embodiments the Ge precursor is a germaniumalkoxide, for example Ge(OEt)₄ or Ge(OMe)₄. In some embodiments, the Geprecursor is TDMAGe. In some embodiments, the Ge precursor includesalkyl and/or alkylamine groups. In some embodiments the Ge-precursor isnot a halide. In some embodiments the Ge-precursor may comprise ahalogen in at least one ligand, but not in all ligands. The germaniumprecursor may be provided with the aid of an inert carrier gas, such asargon.

In some embodiments the second reactant comprises a nitrogen-hydrogenbond. In some embodiments the second reactant is ammonia (NH₃). In someembodiments, the second reactant is molecular nitrogen. In someembodiments the second reactant is a nitrogen containing plasma. In someembodiments, the second reactant comprises an activated or excitednitrogen species. In some embodiments the second reactant may be aprovided in a nitrogen-containing gas pulse that can be a mixture ofnitrogen reactant and inactive gas, such as argon.

In some embodiments, a nitrogen-containing plasma is formed in areactor. In some embodiments, the plasma may be formed in situ on top ofthe substrate or in close proximity to the substrate. In otherembodiments, the plasma is formed upstream of the reaction chamber in aremote plasma generator and plasma products are directed to the reactionchamber to contact the substrate. As will be appreciated by the skilledartisan, in the case of remote plasma, the pathway to the substrate canbe optimized to maximize electrically neutral species and minimize ionsurvival before reaching the substrate.

Irrespective of the second reactant used, in some embodiments of thepresent disclosure, the use of a second reactant does not contributesignificant amounts of nitrogen to the deposited film. According to someembodiments, the resulting germanium film contains less than about 5-at%, less than about 2-at % or even less than about 1-at % nitrogen. Insome embodiments, the nitrogen content of the germanium film is lessthan about 0.5-at % or even less than about 0.2-at %.

In some embodiments hydrogen reactants are not used in the depositionprocess. In some embodiments, no elemental hydrogen (H₂) is provided inat least one deposition cycle, or in the entire deposition process. Insome embodiments, hydrogen plasma is not provided in at least onedeposition cycle or in the entire deposition process. In someembodiments, hydrogen atoms or radicals are not provided in at least onedeposition cycle, or in the entire deposition process.

In some embodiments the Ge precursor comprises at least one amine oralkylamine ligand, such as those presented in formulas (2) through (6)and (8) and (9), and the second reactant comprises NH₃.

Before starting the deposition of the film, the substrate is typicallyheated to a suitable growth temperature, as discussed above. Thepreferred deposition temperature may vary depending on a number offactors such as, and without limitation, the reactant precursors, thepressure, flow rate, the arrangement of the reactor, and the compositionof the substrate including the nature of the material to be depositedon. In some embodiments the deposition temperature is selected to bebetween the temperature where the germanium precursor does not decomposewithout the second precursor, at the lower end, and the temperaturewhere the precursor does decompose by itself, at the upper end. Asdiscussed elsewhere, in some embodiments the temperature may be lessthan about 600° C., less than about 450° C., less than about 400° C.,and in some cases, less than about 375° C. In some embodiments usingGe(OCH₂CH₃)₄ and NH₃ as the germanium and second reactants, thetemperature is about 350° C.

The processing time depends on the thickness of the layer to be producedand the growth rate of the film. In ALD, the growth rate of a thin filmis determined as thickness increase per one cycle. One cycle consists ofthe contacting and removing steps of the precursors and the duration ofone cycle is typically between about 0.2 seconds and about 30 seconds,more preferably between about 1 second and about 10 seconds, but it canbe on order of minutes or more in some cases, for example, where largesurface areas and volumes are present.

In some embodiments the growth rate of the germanium thin films may begreater than or equal to about 2 Å/cycle, greater than or equal to about5 Å/cycle, greater than or equal to about 10 Å/cycle, and, in someembodiments, even greater than about 15 Å/cycle.

In some embodiments the germanium film formed is a relatively puregermanium film. Preferably, aside from minor impurities no other metalor semi-metal elements are present in the film. In some embodiments thefilm comprises less than 1-at % of metal or semi-metal other than Ge. Insome embodiments, the germanium film comprises less than about 5-at % ofany impurity other than hydrogen, preferably less than about 3-at % ofany impurity other than hydrogen, and more preferably less than about1-at % of any impurity other than hydrogen. In some embodiments agermanium film comprises less than about 5 at-% nitrogen, less thanabout 3 at-% nitrogen less than about 2 at-% nitrogen or even less thanabout 1 at-% nitrogen. In some embodiments, a pure germanium filmcomprises less than about 2-at % oxygen, preferably less than about 1-at% or less than about 0.5-at % and even less than about 0.25-at %.

In some embodiments a germanium precursor comprising oxygen is utilizedand the germanium film comprises no oxygen or a small amount of oxygenas an impurity. In some embodiments the germanium film deposited using agermanium precursor comprising oxygen may comprise less than about 2at-% oxygen, less than about 1 at-%, less than about 0.5 at-% or evenless than about 0.25 at-%.

In some embodiments, the germanium film formed has step coverage of morethan about 50%, more than about 80%, more than about 90%, or even morethan about 95% on structures which have high aspect ratios. In someembodiments high aspect ratio structures have an aspect ratio that ismore than about 3:1 when comparing the depth or height to the width ofthe feature. In some embodiments the structures have an aspect ratio ofmore than about 5:1, or even an aspect ratio of 10:1 or greater.

Ge Precursors

A number of different Ge precursors can be used in the selectivedeposition processes. In some embodiments the Ge precursor istetravalent (i.e. Ge has an oxidation state of +IV). In someembodiments, the Ge precursor is not divalent (i.e., Ge has an oxidationstate of +II). In some embodiments, the Ge precursor may comprise atleast one alkoxide ligand. In some embodiments, the Ge precursor maycomprise at least one amine or alkylamine ligand. In some embodimentsthe Ge precursor is a metal-organic or organometallic compound. In someembodiments the Ge precursor comprises at least one halide ligand. Insome embodiments the Ge precursor does not comprise a halide ligand.

In some embodiments the Ge precursor comprises a Ge—O bond. In someembodiments the Ge precursor comprises a Ge—N bond. In some embodimentsthe Ge precursor comprises a Ge—C bond. In some embodiments the Geprecursor does not comprise Ge—H bond. In some embodiments the Geprecursor comprises equal or less than two Ge—H bonds per one Ge atom.

In some embodiments the Ge precursor is not solid at room temperature(e.g., about 20° C.).

For example, Ge precursors from formulas (1) through (9) below may beused in some embodiments.GeOR₄  (1)

Wherein R is can be independently selected from the group consisting ofalkyl and substituted alkyl;GeR_(x)A_(4-x)  (2)

Wherein the x is an integer from 1 to 4;

R is an organic ligand and can be independently selected from the groupconsisting of alkoxides, alkylsilyls, alkyl, substituted alkyl,alkylamines; and

A can be independently selected from the group consisting of alkyl,substituted alkyl, alkoxides, alkylsilyls, alkyl, alkylamines, halide,and hydrogen.Ge(OR)_(x)A_(4-x)  (3)

Wherein the x is an integer from 1 to 4;

R can be independently selected from the group consisting of alkyl andsubstituted alkyl; and

A can be independently selected from the group consisting of alkyl,alkoxides, alkylsilyls, alkyl, substituted alkyl, alkylamines, halide,and hydrogen.Ge(NR^(I)R^(II))₄  (4)

Wherein R^(I) can be independently selected from the group consisting ofhydrogen, alkyl and substituted alkyl; and

R^(II) can be independently selected from the group consisting of alkyland substituted alkyl;Ge(NR^(I)R^(II))_(x)A_(4-x)  (5)

Wherein the x is an integer from 1 to 4;

R^(I) can be independently selected from the group consisting ofhydrogen, alkyl and substituted alkyl; and

R^(II) can be independently selected from the group consisting of alkyland substituted alkyl;

A can be independently selected from the group consisting of alkyl,alkoxides, alkylsilyls, alkyl, substituted alkyl, alkylamines, halide,and hydrogen.Ge_(n)(NR^(I)R^(II))_(2n+2)  (6)

Wherein the n is an integer from 1 to 3;

R^(I) can be independently selected from the group consisting ofhydrogen, alkyl and substituted alkyl; and

R^(II) can be independently selected from the group consisting of alkyland substituted alkyl;Ge_(n)(OR)_(2n+2)  (7)

Wherein the n is an integer from 1 to 3; and

Wherein R can be independently selected from the group consisting ofalkyl and substituted alkyl;Ge_(n)R_(2n+2)  (8)

Wherein the n is an integer from 1 to 3; and

R is an organic ligand and can be independently selected from the groupconsisting of alkoxides, alkylsilyls, alkyl, substituted alkyl,alkylamines.A_(3-x)R_(x)Ge—GeR_(y)A_(3-y)  (9)

Wherein the x is an integer from 1 to 3;

y is an integer from 1 to 3;

R is an organic ligand and can be independently selected from the groupconsisting of alkoxides, alkylsilyls, alkyl, substituted alkyl,alkylamines; and

A can be independently selected from the group consisting of alkyl,alkoxides, alkylsilyls, alkyl, substituted alkyl, alkylamines, halide,and hydrogen.

Preferred options for R include, but are not limited to, methyl, ethyl,propyl, isopropyl, n-butyl, isobutyl, tertbutyl for all formulas, morepreferred in ethyl and methyl. In some embodiments, the preferredoptions for R include, but are not limited to, C₃-C₁₀ alkyls, alkenyls,and alkynyls and substituted versions of those, more preferably C₃-C₆alkyls, alkenyls, and alkenyls and substituted versions of those.

In some embodiments the Ge precursor comprises one or more halides. Forexample, the precursor may comprise 1, 2, or 3 halide ligands. However,as mentioned above, in some embodiments the Ge precursor does notcomprise a halide.

In some embodiments a germane (GeH_(x)) is not used. In some embodimentsa compound comprising Ge and hydrogen may be used. In some embodiments agermane may be used, including, but not limited to, one or more of GeH₄and Ge₂H₆.

In some embodiments alkoxide Ge precursors may be used, including, butnot limited to, one or more of Ge(OMe)₄, Ge(OEt)₄, Ge(O^(i)Pr)₄,Ge(O^(n)Pr)₄ and Ge(O^(t)Bu)₄. In some embodiments the Ge precursor isTDMAGe. In some embodiments the Ge precursor is TDEAGe. In someembodiments the Ge precursor is TEMAGe.

Selective Deposition of Metal or Metal Oxide on Dielectric

As mentioned above, in some embodiments a metal or metal oxide materialis selectively deposited on a first hydrophilic surface of a substraterelative to a second, different surface, such as a conductive surface,metal surface, or H-terminated surface of the same substrate.

In some embodiments metal or metal oxide deposition on the first surfaceof the substrate relative to the second surface of the substrate is atleast about 90% selective, at least about 95% selective, at least about96%, 97%, 98% or 99% or greater selective. In some embodiments metal ormetal oxide deposition only occurs on the first surface and does notoccur on the second surface. In some embodiments metal or metal oxidedeposition on the first surface of the substrate relative to the secondsurface of the substrate is at least about 80% selective, which may beselective enough for some particular applications. In some embodimentsdeposition on the first surface of the substrate relative to the secondsurface of the substrate is at least about 50% selective, which may beselective enough for some particular applications.

In some embodiments the second surface is treated, or deactivated, toinhibit deposition of a metal or metal oxide thereon. For example, ametal surface may be treated by oxidation to provide a metal oxidesurface. In some embodiments a Cu, Ru, Al, Ni, Co, or other noble metalsurface is oxidized to facilitate selective deposition on a dielectricsurface relative to the Cu, Ru, Al, Ni, Co, or other noble metalsurface. In some embodiments the second surface comprises a metalselected individually from Cu, Ni, Co, Al, Ru and other noble metals. Insome embodiments the second surface is a Cu surface. In some embodimentsthe second surface is a Ni surface. In some embodiments the secondsurface is a Co surface. In some embodiments the second surface is an Alsurface. In some embodiments the second surface is a Ru surface. In someembodiments the second surface comprises a noble metal.

In some embodiments the conductive surface comprises an oxide such asCuOx, NiOx, CoOx or RuOx or another noble metal oxide. In someembodiments a conductive surface may no longer be conductive after ithas been treated. For example, a conductive surface may be treated priorto or at the beginning of the selective deposition process, such as byoxidation, and the treated surface may no longer be conductive.

In some embodiments the second surface is not a hydrophilic surface. Insome embodiments a hydrophilic surface may be treated so that it is nolonger a hydrophilic surface. In some embodiments the second surface isa Si surface. In some embodiments the second surface is an H-terminatedsurface. In some embodiments the second surface is treated, for exampleby contacting with a chemical that provides a —SiH3 terminated surface.In some embodiments a Si surface is treated prior to deposition of ametal or metal oxide on a first surface.

In some embodiments the second, metal, surface is oxidized prior todeposition of a metal or metal oxide on a first surface. In someembodiments the second, metal, surface is oxidized at the beginning ofthe deposition process, for example, during the first phase of adeposition cycle. In some embodiments the second, metal, surface isoxidized prior to the first phase of a deposition cycle.

In some embodiments the second surface may be passivated to inhibitdeposition thereon. In some embodiments, for example, the second surfacemay be passivated with alkylsilyl-groups. For example, in someembodiments a second surface is passivated such that it comprisesalkylsilyl-groups, in order to facilitate selective deposition on adielectric surface relative to the second surface. The passivation mayfacilitate selective deposition on the dielectric surface relative to atreated metal surface. For example, deposition of an oxide on the metalsurface may be inhibited by the passivation. In some embodimentspassivation does not include formation of a SAM or a similar monolayerhaving a long carbon chain on the metal surface.

In some embodiments the material selectively deposited on a firstsurface of a substrate relative to a second surface is a metal. In someembodiments the material selectively deposited on a first surface of asubstrate relative to a second surface is a metal oxide. In someembodiments the metal selectively deposited is Fe. In some embodimentsthe metal oxide selectively deposited is a Ni, Fe, or Co oxide. In someembodiments the metal selectively deposited is Ni. In some embodimentsthe metal selectively deposited is Co. In some embodiments selectivedeposition of a metal oxide may be achieved by oxidation of aselectively deposited metal. In some embodiments a metal is firstselectively deposited and subsequently oxidized to form a metal oxide.In some embodiments a metal is not oxidized after being selectivelydeposited.

ALD type selective deposition processes, such as the process as shown inFIG. 1 and described above can be used to selectively deposit a metal ormetal oxide on a first surface of a substrate relative to a secondsurface. In some embodiments the first precursor is a first metalprecursor. In some embodiments the first precursor is a first metaloxide precursor. In some embodiments the second reactant comprises anoxygen source. In some embodiments the second reactant comprises anoxygen source as described herein in relation to selective deposition ofa dielectric on a dielectric.

Suitable nickel precursors may be selected by the skilled artisan. Ingeneral, nickel compounds where the metal is bound or coordinated tooxygen, nitrogen, carbon or a combination thereof are preferred. In someembodiments the nickel precursors are organic compounds. In someembodiments the nickel precursor is a metalorganic compound. In someembodiments the nickel precursor is a metal organic compound comprisingbidentate ligands. In some embodiments the nickel precursor isbis(4-N-ethylamino-3-penten-2-N-ethyliminato)nickel (ii).

In some embodiments, nickel precursors can be selected from the groupconsisting of nickel betadiketonate compounds, nickel betadiketiminatocompounds, nickel aminoalkoxide compounds, nickel amidinate compounds,nickel cyclopentadienyl compounds, nickel carbonyl compounds andcombinations thereof. In some embodiments, X(acac)y or X(thd)y compoundsare used, where X is a metal, y is generally, but not necessarilybetween 2 and 3 and thd is 2,2,6,6-tetramethyl-3,5-heptanedionato. Someexamples of suitable betadiketiminato (e.g., Ni(pda)2) compounds arementioned in U.S. Patent Publication No. 2009-0197411 A1, the disclosureof which is incorporated herein in its entirety. Some examples ofsuitable amidinate compounds (e.g., Ni(iPr-AMD)2) are mentioned in U.S.Patent Publication No. 2006-0141155 A1, the disclosure of which isincorporated herein in its entirety.

The nickel precursor may also comprise one or more halide ligands. Inpreferred embodiments, the precursor is nickel betadiketiminatocompound, such bis(4-N-ethylamino-3-penten-2-N-ethyliminato)nickel (II)[Ni(EtN-EtN-pent)2], nickel ketoiminate, suchbis(3Z)-4-nbutylamino-pent-3-en-2-one-nickel(II), nickel amidinatecompound, such as methylcyclopentadienyl-isopropylacetamidinate-nickel(II), nickel betadiketonato compound, such as Ni(acac)2,Ni(thd)2 ornickel cyclopentadienyl compounds, such Ni(cp)2, Ni(Mecp)2, Ni(Etcp)2 orderivatives thereof, such asmethylcyclopentadienyl-isopropylacetamidinate-nickel (II). In morepreferred embodiment, the precursor isbis(4-N-ethylamino-3-penten-2-N-ethyliminato)nickel (II).

In some embodiments the first Ni precursor isbis(4-N-ethylamino-3-penten-2-N-ethyliminato)nickel (II).

In some embodiments the first precursor used in a selective depositionprocess for depositing Co or Co oxide on a first surface of a substraterelative to a second surface is a Co precursor. In some embodiments theCo precursor is a Co beta-diketoiminato compound. In some embodimentsthe Co precursor is a Co ketoiminate compound. In some embodiments theCo precursor is a Co amidinate compound. In some embodiments the Coprecursor is a Co beta-diketonate compound. In some embodiments the Coprecursor contains at least one ketoimine ligand or a derivativethereof. In some embodiments the Co precursor contains at least oneamidine ligand or a derivative thereof. In some embodiments the Coprecursor contains at least one ketonate ligand or a derivative thereof.

In some embodiments the first precursor used in a selective depositionprocess for depositing Fe or Fe oxide on a first surface of a substraterelative to a second surface is a Fe precursor. In some embodiments theFe precursor is Cp₂Fe or derivative thereof. In some embodiments the Feprecursor contains at least one cyclopentadienyl ligand (Cp),substituted cyclopentadienyl ligand or a derivative thereof. In someembodiments the Fe precursor contains at least one carbonyl ligand (—CO)or a derivative thereof. In some embodiments the Fe precursor containsat least one carbonyl ligand (—CO) and at least one organic ligand, suchas a cyclopentadienyl ligand (Cp) or a substituted cyclopentadienylligand or a derivative thereof. In some embodiments the Fe precursor isFe(acac)₂. In some embodiments the Fe precursor is Fe-alkoxide, such asiron(III) tert-butoxide (Fe₂(O^(t)Bu)₆). In some embodiments the Feprecursor is Fe(CO)₅.

In some embodiments the second reactant in an ALD process forselectively depositing a metal or metal oxide is selected from hydrogenand forming gas. In other embodiments the second reactant may be analcohol, such as EtOH.

In some embodiments the second reactant is an organic reducing agent.The organic reducing agents preferably have at least one functionalgroup selected from the group consisting of alcohol (—OH), as mentionedabove, or aldehyde (—CHO), or carboxylic acid (—COOH).

Reducing agents containing at least one alcohol group may be selectedfrom the group consisting of primary alcohols, secondary alcohols,tertiary alcohols, polyhydroxy alcohols, cyclic alcohols, aromaticalcohols, halogenated alcohols, and other derivatives of alcohols.

Preferred primary alcohols have an —OH group attached to a carbon atomwhich is bonded to another carbon atom, in particular primary alcoholsaccording to the general formula (I):R1-OH  (I)

wherein R1 is a linear or branched C1-C20 alkyl or alkenyl groups,preferably methyl, ethyl, propyl, butyl, pentyl or hexyl. Examples ofpreferred primary alcohols include methanol, ethanol, propanol, butanol,2-methyl propanol and 2-methyl butanol.

Preferred secondary alcohols have an —OH group attached to a carbon atomthat is bonded to two other carbon atoms. In particular, preferredsecondary alcohols have the general formula (II):

wherein each R1 is selected independently from the group of linear orbranched C1-C20 alkyl and alkenyl groups, preferably methyl, ethyl,propyl, butyl, pentyl or hexyl. Examples of preferred secondary alcoholsinclude 2-propanol and 2-butanol.

Preferred tertiary alcohols have an —OH group attached to a carbon atomthat is bonded to three other carbon atoms. In particular, preferredtertiary alcohols have the general formula (III):

wherein each R1 is selected independently from the group of linear orbranched C1-C20 alkyl and alkenyl groups, preferably methyl, ethyl,propyl, butyl, pentyl or hexyl. An example of a preferred tertiaryalcohol is tert-butanol.

Preferred polyhydroxy alcohols, such as diols and triols, have primary,secondary and/or tertiary alcohol groups as described above. Examples ofpreferred polyhydroxy alcohol are ethylene glycol and glycerol.

Preferred cyclic alcohols have an —OH group attached to at least onecarbon atom which is part of a ring of 1 to 10, more preferably 5-6carbon atoms.

Preferred aromatic alcohols have at least one —OH group attached eitherto a benzene ring or to a carbon atom in a side chain. Examples ofpreferred aromatic alcohols include benzyl alcohol, o-, p- and m-cresoland resorcinol.

Preferred halogenated alcohols have the general formula (IV):CHnX3-n-R2-OH  (IV)

wherein X is selected from the group consisting of F, Cl, Br and I, n isan integer from 0 to 2 and R2 is selected from the group of linear orbranched C1-C20 alkyl and alkenyl groups, preferably methyl, ethyl,propyl, butyl, pentyl or hexyl. More preferably X is selected from thegroup consisting of F and Cl and R2 is selected from the groupconsisting of methyl and ethyl. An example of a preferred halogenatedalcohol is 2,2,2-trifluoroethanol.

Other derivatives of alcohols that may be used include amines, such asmethyl ethanolamine.

Preferred reducing agents containing at least one aldehyde group (—CHO)are selected from the group consisting of compounds having the generalformula (V), alkanedial compounds having the general formula (VI),halogenated aldehydes and other derivatives of aldehydes.

Thus, in some embodiments reducing agents are aldehydes having thegeneral formula (V):R3-CHO  (V)

wherein R3 is selected from the group consisting of hydrogen and linearor branched C1-C20 alkyl and alkenyl groups, preferably methyl, ethyl,propyl, butyl, pentyl or hexyl. More preferably, R3 is selected from thegroup consisting of methyl or ethyl. Examples of preferred compoundsaccording to formula (V) are formaldehyde, acetaldehyde andbutyraldehyde.

In other embodiments reducing agents are aldehydes having the generalformula (VI):OHC—R4-CHO  (VI)

wherein R4 is a linear or branched C1-C20 saturated or unsaturatedhydrocarbon. Alternatively, the aldehyde groups may be directly bondedto each other (R4 is null).

Reducing agents containing at least one —COOH group may be selected fromthe group consisting of compounds of the general formula (VII),polycarboxylic acids, halogenated carboxylic acids and other derivativesof carboxylic acids.

Thus, in some embodiment preferred reducing agents are carboxylic acidshaving the general formula (VII):R5-COOH  (VII)

wherein R5 is hydrogen or linear or branched C1-C20 alkyl or alkenylgroup, preferably methyl, ethyl, propyl, butyl, pentyl or hexyl, morepreferably methyl or ethyl. Examples of preferred compounds according toformula (VII) are formic acid and acetic acid, most preferably formicacid (HCOOH).

Selective Deposition of Dielectric on Dielectric

As mentioned above, in some embodiments a dielectric material isselectively deposited on a first dielectric surface of a substraterelative to a second, different surface, such as a conductive surface,metal surface, or H-terminated surface of the same substrate.

In some embodiments dielectric deposition on the first surface of thesubstrate relative to the second surface of the substrate is at leastabout 90% selective, at least about 95% selective, at least about 96%,97%, 98% or 99% or greater selective. In some embodiments dielectricdeposition only occurs on the first surface and does not occur on thesecond surface. In some embodiments dielectric deposition on the firstsurface of the substrate relative to the second surface of the substrateis at least about 80% selective, which may be selective enough for someparticular applications. In some embodiments deposition on the firstsurface of the substrate relative to the second surface of the substrateis at least about 50% selective, which may be selective enough for someparticular applications.

In some embodiments the second surface is treated, or deactivated, toinhibit deposition of a dielectric thereon. For example, a metal surfacemay be treated by oxidation to provide a metal oxide surface. In someembodiments a Cu, Ru, Al, Ni, Co, or other noble metal surface isoxidized to facilitate selective deposition on a dielectric surfacerelative to the Cu, Ru, Al, Ni, Co, or other noble metal surface. Insome embodiments the second surface comprises a metal selectedindividually from Cu, Ni, Co, Al, Ru and other noble metals. In someembodiments the second surface is a Cu surface. In some embodiments thesecond surface is a Ni surface. In some embodiments the second surfaceis a Co surface. In some embodiments the second surface is an Alsurface. In some embodiments the second surface is a Ru surface. In someembodiments the second surface comprises a noble metal.

In some embodiments the conductive surface comprises an oxide such asCuOx, NiOx, CoOx or RuOx or another noble metal oxide. In someembodiments a conductive surface may no longer be conductive after ithas been treated. For example, a conductive surface may be treated priorto or at the beginning of the selective deposition process, such as byoxidation, and the treated surface may no longer be conductive.

In some embodiments the second, metal, surface is oxidized prior todeposition of a dielectric on a first surface. In some embodiments thesecond, metal, surface is oxidized at the beginning of the depositionprocess, for example, during the first phase of a deposition cycle. Insome embodiments the second, metal surface is oxidized prior to thefirst phase of a deposition cycle. In some embodiments the second,metal, surface is purposefully oxidized with an oxygen source. In someembodiments the second, metal, surface is oxidized in the ambient airand/or contains native oxide. In some embodiments the second, metal,surface contains an oxide which has been deposited.

In some embodiments the second surface may be passivated to inhibitdeposition thereon. In some embodiments, for example, the second surfacemay be passivated with alkylsilyl-groups. For example, in someembodiments a second surface is passivated such that it comprisesalkylsilyl-groups, in order to facilitate selective deposition on adielectric surface relative to the second surface. The passivation mayfacilitate selective deposition on the dielectric surface relative tothe treated metal surface. For example, deposition of an oxide on thefirst metal surface may be inhibited by the passivation. In someembodiments passivation does not include formation of a SAM or a similarmonolayer having a long carbon chain on the metal surface.

Selective Deposition of GeO₂ on Dielectric

GeO₂ may be deposited by an ALD type process on a first dielectricsurface of a substrate relative to a second, different surface of thesame substrate. In some embodiments the second surface may be aconductive surface, a metal surface, or an H-terminated surface. In someembodiments the GeO₂ is deposited by a method as described in U.S.application Ser. No. 13/802,393, filed Mar. 13, 2013, which is herebyincorporated by reference. In some embodiments the dielectric surface isa hydrophilic OH-terminated surface. For example, the dielectric surfacecan be a SiO₂ surface, a low-k surface, preferably comprising OH-groups,or a GeO₂ surface. The second surface may be, for example, a Cu, Ru, Al,Ni, Co, or other noble metal surface. In some embodiments the secondsurface comprises a metal selected individually from Cu, Ni, Co, Al, Ruand other noble metals. In some embodiments the second surface is a Cusurface. In some embodiments the second surface is a Ni surface. In someembodiments the second surface is a Co surface. In some embodiments thesecond surface is an Al surface. In some embodiments the second surfaceis a Ru surface. In some embodiments the second surface comprises anoble metal. As discussed above, in some embodiments a dielectricsurface may be treated to increase the amount of OH-groups on thesurface. In some embodiments the second surface may be an oxide. In someembodiments the second surface may be a metal surface that has beenoxidized.

In some embodiments the conductive surface comprises an oxide such asCuOx, NiOx, CoOx or RuOx or another noble metal oxide. In someembodiments a conductive surface may no longer be conductive after ithas been treated. For example, a conductive surface may be treated priorto or at the beginning of the selective deposition process, such as byoxidation, and the treated surface may no longer be conductive.

In some embodiments the second, metal, surface is purposefully oxidizedwith an oxygen source. In some embodiments the second, metal, surfacehas oxidized in the ambient air and/or contains native oxide. In someembodiments the second, metal, surface contains an oxide which has beendeposited.

As previously discussed, in some embodiments, the metal surface isoxidized prior to deposition in order to facilitate selective depositionof GeO₂ on the dielectric surface relative to the metal surface. In someembodiments a second reactant in a selective deposition process mayserve to oxidize the metal surface. Thus, in some embodiments the secondreactant is provided first in the initial ALD cycle, or prior to thefirst ALD cycle. In some embodiments the metal surface is oxidized priorto beginning the selective deposition process.

In some embodiments the metal surface is passivated prior to depositionin order to facilitate selective deposition of GeO₂ on the dielectricsurface relative to the metal surface. For example, the metal surfacecan be provided with alkylsilyl groups.

In some embodiments GeO2 deposition on the first surface of thesubstrate relative to the second surface of the substrate is at leastabout 90% selective, at least about 95% selective, at least about 96%,97%, 98% or 99% or greater selective. In some embodiments GeO₂deposition only occurs on the first surface and does not occur on thesecond surface. In some embodiments GeO₂ deposition on the first surfaceof the substrate relative to the second surface of the substrate is atleast about 80% selective, which may be selective enough for someparticular applications. In some embodiments deposition on the firstsurface of the substrate relative to the second surface of the substrateis at least about 50% selective, which may be selective enough for someparticular applications.

Referring to FIG. 4 and according to a preferred embodiment a substratecomprising a first surface and a second surface is provided at step 410and a dielectric, here GeO₂, is selectively deposited on a first surfaceof a substrate by an ALD-type process comprising multiple cycles, eachcycle 400 comprising:

contacting the surface of a substrate with a vaporized first precursor,here a Ge-alkylamide, at step 430;

removing excess first precursor and reaction by products, if any, fromthe surface at step 440;

contacting the surface of the substrate with a second vaporizedreactant, here H₂O at step 450;

removing from the surface, at step 460, excess second reactant and anygaseous by-products formed in the reaction between the first precursorlayer on the first surface of the substrate and the second reactant,and;

repeating, at step 470, the contacting and removing steps until adielectric, here GeO₂, thin film of the desired thickness has beenformed on a first surface of the substrate.

As mentioned above, in some embodiments one or more surfaces of thesubstrate may be treated in order to enhance deposition on one surfacerelative to one or more different surfaces prior to beginning thedeposition process 400. In FIG. 4 this is indicated by step 420 in whichthe second, metal surface is deactivated, such as by passivation oroxidation prior to the deposition of the dielectric, here GeO₂.

In some embodiments germanium oxide, preferably GeO₂, is deposited fromalternately and sequentially contacting the substrate with a Geprecursor and a second reactant, such as water, ozone, oxygen plasma,oxygen radicals, or oxygen atoms. In some embodiments the secondreactant is not water. The Ge precursor preferably comprises Ge(OEt)4 orTDMAGe.

The Ge precursor employed in the ALD type processes may be solid,liquid, or gaseous material under standard conditions (room temperatureand atmospheric pressure), provided that the Ge precursor is in vaporphase before it is contacted with the substrate surface. Contacting thesurface of a substrate with a vaporized precursor means that theprecursor vapor is in contact with the surface of the substrate for alimited period of time. Typically, the contacting time is from about0.05 seconds to about 10 seconds. However, depending on the substratetype and its surface area, the contacting time may be even higher thanabout 10 seconds.

In some embodiments, the reactants and reaction by-products can beremoved from the substrate surface by stopping the flow of secondreactant while continuing the flow of an inert carrier gas. In someembodiments the substrate is moved such that different reactantsalternately and sequentially contact the surface of the substrate in adesired sequence for a desired time. In some embodiments the removingsteps, 140 and 160 are not performed. In some embodiments no reactantmay be removed from the various parts of a chamber. In some embodimentsthe substrate is moved from a part of the chamber containing a firstprecursor to another part of the chamber containing the second reactant.In some embodiments the substrate is moved from a first reaction chamberto a second, different reaction chamber.

Preferably, for a 300 mm wafer in a single wafer ALD reactor, thesubstrate surface is contacted with a Ge precursor for from about 0.05seconds to about 10 seconds, more preferably for from about 0.1 secondsto about 5 seconds and most preferably for from about 0.3 seconds toabout 3.0 seconds. The substrate surface is contacted with the secondprecursor preferably for from about 0.05 seconds to about 10 seconds,more preferably for from about 0.1 seconds to about 5 seconds, mostpreferably for from about 0.2 seconds to about 3.0 seconds. However,contacting times can be on the order of minutes in some cases. Theoptimum contacting time can be readily determined by the skilled artisanbased on the particular circumstances.

As mentioned above, in some embodiments the Ge precursor is Ge(OEt)₄ orTDMAGe. Other possible germanium precursors that can be used in someembodiments are described below. In some embodiments, the Ge precursoris Ge(OMe)₄. In some embodiments the Ge-precursor is not a halide. Insome embodiments the Ge-precursor may comprise a halogen in at least oneligand, but not in all ligands.

In certain preferred embodiments GeO₂ is selectively deposited on afirst surface of a substrate relative to a second, different surface ofthe substrate by an ALD type process, comprising multiple cycles, eachcycle comprising alternately and sequentially contacting the substratewith vapor phase Ge— alkylamide and a second reactant comprising water.

In certain preferred embodiments GeO₂ is selectively deposited on afirst surface of a substrate relative to a second, different surface ofthe substrate by an ALD type process, comprising multiple cycles, eachcycle comprising alternately and sequentially contacting the substratewith a vapor phase Ge precursor with the formula Ge(NR^(I)R^(II))₄, anda second reactant comprising water, wherein R^(I) can be independentlyselected from the group consisting of hydrogen, alkyl and substitutedalkyl, wherein R^(I) can be preferably independently selected from thegroup consisting of C1-C3 alkyls, such as methyl, ethyl, n-propyl, andi-propyl, most preferably methyl or ethyl; and wherein R^(II) can beindependently selected from the group consisting of alkyl andsubstituted alkyl, wherein R^(II) can be preferably independentlyselected from the group consisting of C1-C3 alkyls, such as methyl,ethyl, n-propyl, and i-propyl, most preferably methyl or ethyl.

The second reactant may be an oxygen-containing gas pulse and can be amixture of oxygen and inactive gas, such as nitrogen or argon. In someembodiments the second reactant may be a molecular oxygen-containinggas. The preferred oxygen content of the second reactant gas is fromabout 10% to about 25%. Thus, in some embodiments the second reactantmay be air. In some embodiments, the second reactant is molecularoxygen. In some embodiments, the second reactant comprises an activatedor excited oxygen species. In some embodiments, the second reactantcomprises ozone. The second reactant may be pure ozone or a mixture ofozone, molecular oxygen, and another gas, for example an inactive gassuch as nitrogen or argon. Ozone can be produced by an ozone generatorand it is most preferably introduced into the reaction space with theaid of an inert gas of some kind, such as nitrogen, or with the aid ofoxygen. In some embodiments, ozone is provided at a concentration fromabout 5 vol-% to about 40 vol-%, and preferably from about 15 vol-% toabout 25 vol-%. In other embodiments, the second reactant is oxygenplasma.

In some embodiments, the surface of the substrate is contacted withozone or a mixture of ozone and another gas. In other embodiments, ozoneis formed inside a reactor, for example by conducting oxygen containinggas through an arc. In other embodiments, an oxygen containing plasma isformed in a reactor. In some embodiments, a plasma may be formed in situon top of the substrate or in close proximity to the substrate. In otherembodiments, a plasma is formed upstream of a reaction chamber in aremote plasma generator and plasma products are directed to the reactionchamber to contact the substrate. As will be appreciated by the skilledartisan, in the case of a remote plasma, the pathway to the substratecan be optimized to maximize electrically neutral species and minimizeion survival before reaching the substrate.

In some embodiments the second reactant is a second reactant other thanwater. Thus, in some embodiments water is not provided in any ALD cyclefor selectively depositing GeO₂.

A number of different Ge precursors can be used in the selectivedeposition processes. In some embodiments the Ge precursor istetravalent (i.e. Ge has an oxidation state of +IV). In someembodiments, the Ge precursor is not divalent (i.e., Ge has an oxidationstate of +II). In some embodiments, the Ge precursor may comprise atleast one alkoxide ligand. In some embodiments, the Ge precursor maycomprise at least one amine or alkylamine ligand. In some embodimentsthe Ge precursor is a metal-organic or organometallic compound. In someembodiments the Ge precursor comprises at least one halide ligand. Insome embodiments the Ge precursor does not comprise a halide ligand.

For example, Ge precursors from formulas (1) through (9), as previouslydiscussed above, may be used in some embodiments.

In some embodiments the Ge precursor comprises at least one amine oralkylamine ligand, such as those presented in formulas (2) through (6)and (8) and (9), and the oxygen precursor comprises water.

In some embodiments the Ge precursor comprises at least one alkoxy,amine or alkylamine ligand. In some embodiments the GeO₂ is deposited byan ALD process using water and a Ge-alkylamine precursor. In someembodiments the Ge precursor is Ge(NMe₂)₄ or Ge(NEt₂)₄ or Ge(NEtMe)₄.

Before starting the deposition of the film, the substrate is typicallyheated to a suitable growth temperature, as discussed above. Thepreferred deposition temperature may vary depending on a number offactors such as, and without limitation, the reactant precursors, thepressure, flow rate, the arrangement of the reactor, and the compositionof the substrate including the nature of the material to be depositedon.

The processing time depends on the thickness of the layer to be producedand the growth rate of the film. In ALD, the growth rate of a thin filmis determined as thickness increase per one cycle. One cycle consists ofthe contacting and removing steps of the precursors and the duration ofone cycle is typically between about 0.2 seconds and about 30 seconds,more preferably between about 1 second and about 10 seconds, but it canbe on order of minutes or more in some cases, for example, where largesurface areas and volumes are present.

In some embodiments the GeO₂ film formed is a pure GeO₂ film.Preferably, aside from minor impurities no other metal or semi-metalelements are present in the film. In some embodiments the film comprisesless than 1-at % of metal or semi-metal other than Ge. In someembodiments the GeO₂ film is stoichiometric. In some embodiments, a pureGeO₂ film comprises less than about 5-at % of any impurity other thanhydrogen, preferably less than about 3-at % of any impurity other thanhydrogen, and more preferably less than about 1-at % of any impurityother than hydrogen.

In some embodiments, the GeO₂ film formed has step coverage of more thanabout 80%, more preferably more than about 90%, and most preferably morethan about 95% in structures which have high aspect ratios. In someembodiments high aspect ratio structures have an aspect ratio that ismore than about 3:1 when comparing the depth or height to the width ofthe feature. In some embodiments the structures have an aspect ratio ofmore than about 5:1, or even an aspect ratio of 10:1 or greater.

Selective Deposition of SiO₂ on Dielectric

SiO₂ may be deposited by an atomic layer deposition type process on afirst dielectric surface of a substrate relative to a second surface ofthe same substrate. In some embodiments the dielectric surface is ahydrophilic OH-terminated surface. For example, the dielectric surfacecan be a SiO₂ surface, a low-k surface, preferably comprising OH-groups,or GeO₂ surface. In some embodiments the second surface may be aconductive surface, a metal surface, or a H-terminated surface. Thesecond surface may be, for example, a Cu, Ru, Al, Ni, Co, or other noblemetal surface. In some embodiments the second surface comprises a metalselected individually from Cu, Ni, Co, Al, Ru and other noble metals. Insome embodiments the second surface is a Cu surface. In some embodimentsthe second surface is a Ni surface. In some embodiments the secondsurface is a Co surface. In some embodiments the second surface is an Alsurface. In some embodiments the second surface is a Ru surface. In someembodiments the second surface comprises a noble metal. As discussedabove, in some embodiments a dielectric surface may be treated toincrease the amount of OH-groups on the surface.

In some embodiments the conductive surface comprises an oxide such asCuOx, NiOx, CoOx or RuOx or another noble metal oxide. In someembodiments a conductive surface may no longer be conductive after ithas been treated. For example, a conductive surface may be treated priorto or at the beginning of the selective deposition process, such as byoxidation, and the treated surface may no longer be conductive.

In some embodiments the second, metal, surface is purposefully oxidizedwith an oxygen source. In some embodiments the second, metal, surfacehas oxidized in the ambient air and/or contains native oxide. In someembodiments the second, metal, surface contains an oxide which has beendeposited.

In some embodiments SiO₂ deposition on the first surface of thesubstrate relative to the second surface of the substrate is at leastabout 90% selective, at least about 95% selective, at least about 96%,97%, 98% or 99% or greater selective. In some embodiments SiO₂deposition only occurs on the first surface and does not occur on thesecond surface. In some embodiments SiO₂ deposition on the first surfaceof the substrate relative to the second surface of the substrate is atleast about 80% selective, which may be selective enough for someparticular applications. In some embodiments deposition on the firstsurface of the substrate relative to the second surface of the substrateis at least about 50% selective, which may be selective enough for someparticular applications.

In a preferred embodiment SiO₂ is selectively deposited by an ALD typeprocess using an aminosilane as the Si precursor and ozone as the secondreactant. In some embodiments the SiO₂ is deposited by an ALD processusing ozone and an aminosilane, such as bis(diethylamino)silaneprecursor. Such methods are known in the art and can be adapted todeposit selectively on the dielectric material relative to a metal.

In some embodiments, the metal surface is oxidized prior to depositionin order to facilitate selective deposition of SiO₂ on the dielectricsurface relative to the metal surface. In some embodiments an oxygensource in a selective deposition process may serve to oxidize the metalsurface. Thus, in some embodiments the second reactant is provided firstin the initial ALD cycle, or prior to the first ALD cycle. In someembodiments the metal surface is oxidized prior to beginning theselective deposition process.

In some embodiments the metal surface is passivated prior to depositionin order to facilitate selective deposition of SiO₂ on the dielectricsurface relative to the metal surface. For example, the metal surfacecan be provided with alkylsilyl groups.

Referring to FIG. 5 and according to a preferred embodiment a substratecomprising a first surface and a second surface is provided at step 510and a dielectric, here SiO₂, is selectively deposited on a first surfaceof a substrate by an ALD-type process comprising multiple cycles, eachcycle 500 comprising:

contacting the surface of a substrate with a vaporized first precursor,here an aminosilane, at step 530;

removing excess first precursor and reaction by products, if any, fromthe surface at step 540;

contacting the surface of the substrate with a second vaporizedreactant, here ozone, at step 550;

removing from the surface, at step 560, excess second reactant and anygaseous by-products formed in the reaction between the first precursorlayer on the first surface of the substrate and the second reactant,and;

repeating, at step 570, and removing steps until a dielectric, hereSiO₂, thin film of the desired thickness has been formed on a firstsurface of the substrate.

As mentioned above, in some embodiments one or more surfaces of thesubstrate may be treated in order to enhance deposition on one surfacerelative to one or more different surfaces prior to beginning thedeposition process 500. In FIG. 5 this is indicated by step 520 in whichthe second, metal surface is deactivated, such as by passivation oroxidation prior to the deposition of the dielectric, here SiO₂.

In some embodiments the deposition process 500 is operated at atemperature lower than 450° C. In some embodiments the depositionprocess if operated at 400° C. In some embodiments the entire depositionprocess is carried out at the same temperature.

In some embodiments the SiO₂ selective deposition can be carried out ata wide range of pressure conditions, but it is preferred to operate theprocess at reduced pressure. The pressure in a reaction chamber istypically from about 0.01 to about 500 mbar or more. However, in somecases the pressure will be higher or lower than this range, as can bereadily determined by the skilled artisan. The pressure in a singlewafer reactor is preferably maintained between about 0.01 mbar and 50mbar, more preferably between about 0.1 mbar and 10 mbar. The pressurein a batch ALD reactor is preferably maintained between about 1 mTorrand 500 mTorr, more preferably between about 30 mTorr and 200 mTorr.

In some embodiments the SiO₂ deposition temperature is kept low enoughto prevent thermal decomposition of the gaseous source chemicals. On theother hand, the deposition temperature is kept high enough to provideactivation energy for the surface reactions, to prevent thephysisorption of source materials and minimize condensation of gaseousreactants in the reaction space. Depending on the reactants andreactors, the deposition temperature is typically about 20° C. to about500° C., preferably about 150° C. to about 350° C., more preferablyabout 250° C. to about 300° C.

The silicon source temperature is preferably set below the deposition orsubstrate temperature. This is based on the fact that if the partialpressure of the source chemical vapor exceeds the condensation limit atthe substrate temperature, controlled layer-by-layer growth of the thinfilm is compromised. In some embodiments, the silicon source temperatureis from about 30 to about 150° C. In some embodiments the silicon sourcetemperature is greater than about 60° C. during the deposition. In someembodiments, where greater doses are needed, for example in batch ALD,the silicon source temperature is from about 90° C. to about 200° C.,preferably from about 130° C. to about 170° C.

In some embodiments, the reactants and reaction by-products can beremoved from the substrate surface by stopping the flow of secondreactant while continuing the flow of an inert carrier gas. In someembodiments the substrate is moved such that different reactantsalternately and sequentially contact the surface of the substrate in adesired sequence for a desired time. In some embodiments the removingsteps, 140 and 160 are not performed. In some embodiments no reactantmay be removed from the various parts of a chamber. In some embodimentsthe substrate is moved from a part of the chamber containing a firstprecursor to another part of the chamber containing the second reactant.In some embodiments the substrate is moved from a first reaction chamberto a second, different reaction chamber.

In some embodiments SiO₂ is selectively deposited using an ALD typeprocess as described herein.

In some embodiments the growth rate of the thin film comprising silicondioxide is preferably above 0.7 Å/cycle. In other embodiments the growthrate is above 0.8 Å/cycle and in still other embodiments the growth rateis above 1.0 Å/cycle, and preferably in the range of 1.0 to 1.2 Å/cycle.

In some embodiments the selectively deposited silicon dioxide has lessthan 2 at-% of nitrogen as an impurity. In other embodiments the SiO₂comprise less than 1 at-% of nitrogen, or even less than 0.5 at-%nitrogen as an impurity. Similarly, in some embodiments the SiO₂comprise less than 1 at-% carbon as an impurity and in some cases lessthan 0.5 at-% carbon as an impurity.

In some embodiments the selectively deposited silicon oxide has a stepcoverage of more than 80%, in other embodiments preferably more than 90%and in other embodiments preferably more than 95%.

In certain preferred embodiments SiO₂ is selectively deposited on afirst surface of a substrate relative to a second, different surface ofthe substrate by an ALD type process, comprising multiple cycles, eachcycle comprising alternately and sequentially contacting the substratewith vapor phase BDEAS and a second reactant comprising ozone.

Si Precursors

In some embodiments the silicon precursor can comprise silane, siloxane,or silazane compounds. In some embodiments the SiO₂ is deposited usingprecursors as described in U.S. Pat. No. 7,771,533, which is herebyincorporated by reference. For example, the Si precursor from theformulas (1) through (3) below may be used in some embodiments.Si_(m)L_(2m+2)  (1)Si_(y)O_(y-1)L_(2y+2)  (2)Si_(y)NH_(y-1)L_(2y+2)  (3)

Wherein L can be independently selected from the group consisting of F,C1, Br, I, alkyl, aryl, alkoxy, vinyl, cyano, amino, silyl, alkylsilyl,alkoxysilyl, silylene an alkylsiloxane. In some embodiments alkyl andalkoxy groups can be linear or branched and contain at least onesubstituent. In some embodiments alkyl and alkoxy groups contain 1-10carbon atoms, preferably 1-6 carbon atoms.

In some embodiments the silicon precursor can preferably compriseamino-substituted silanes and silazanes, such as 3-aminoalkyltrialkoxysilanes, for example 3-aminopropyltriethoxy silaneNH₂—CH₂CH₂CH₂—Si(O—CH₂CH₃)₃(AMTES) and 3-aminopropyltrimethoxy silane(NH₂—CH₂CH₂CH₂—Si(O—CH₃)₃(AMTMS) and hexa-alkyldisilazane(CH₃)₃Si—NH—Si(CH₃)₃(HMDS).

In some embodiments the SiO₂ is deposited using precursors as describedin U.S. Pat. No. 8,501,637 which is hereby incorporated by reference. Insome embodiments, the silicon precursor is preferably a disilane and hasa Si—Si bond. Organic compounds having a Si—Si bond and an NH_(x) groupeither attached directly to silicon (to one or more silicon atoms) or toa carbon chain attached to silicon are used in some embodiments. In someembodiments organosilicon compounds are used, which may or may notcomprise Si—Si bonds. More preferably the silicon compound has theformula:R^(III) _(3-x)(R^(II)R^(I)N)_(x)—Si—Si—(N—R^(I)R^(II))_(y)R^(III)_(3-y),  (I)

wherein,

x is selected from 1 to 3;

y is selected from 1 to 3;

R^(I) is selected from the group consisting of hydrogen, alkyl, andsubstituted alkyl;

R^(II) is selected from the group consisting of alkyl and substitutedalkyl; and

R^(III) is selected from the group consisting of hydrogen, hydroxide(—OH), amino (—NH₂), alkoxy, alkyl, and substituted alkyl;

and wherein the each x, y, R^(III), R^(II) and R^(I) can be selectedindependently from each other.

In some embodiments the silicon compound ishexakis(monoalkylamino)disilane:(R^(II)—NH)₃—Si—Si—(NH—R^(II))₃  (II)

In other embodiments the silicon compound ishexakis(ethylamino)disilane:(Et-NH)₃—Si—Si—(NH-Et)₃  (II)

In other embodiments the silicon compound is(CH₃—O)₃—Si—Si—(O—CH₃)₃  (IV)

In some embodiments, the silicon compound ishexakis(monoalkylamino)disilane (R^(II)—NH)₃—Si—Si—(NH—R^(II))₃ andR^(II) is selected from the group consisting of alkyl and substitutedalkyl.

In some embodiments the SiO₂ is deposited using precursors as describedin U.S. Publication No. 2009/0232985 which is hereby incorporated byreference. In some embodiments the deposition temperature can be as lowas room temperature and up to 500° C., with an operating pressure of0.1-100 Torr (13 to 13300 Pa). High quality films, with very low carbonand hydrogen contents, are preferably deposited between 200 and 400° C.at a pressure between 0.1-10 Torr (13 to 1330 Pa).

In some embodiments the Si precursor can comprise less than 100 ppm ofH₂ and can be selected from the group consisting of:

DSO Disiloxane (SiH₃)₂O

Bis(diethylamino)silane SiH₂(NEt₂)₂

BDMAS Bis(dimethylamino)silane SiH₂(NMe₂)₂

TriDMAS Tris(diethylamino)silane SiH(NMe₂)₃

Bis(trimethylsilylamino)silane SiH₂(NHSiMe₃)₂

TEAS Tetrakis(ethylamino)silane Si(NHEt)₄

TEOS Tetrakis(ethoxy)silane Si(OEt)₄

BTESE Bis(triethoxysilyl)ethane (EtO)₃Si—CH₂—CH₂—Si(OEt)₃

In some embodiments the Si precursor is an aminosilane of the generalformula (R1R2N)nSiH_(4-x), where x is comprised between 1 and 4, whereR1 and R2 are independently H or a C1-C6 linear, branched or cycliccarbon chains. Preferably the Si precursor is an aminosilane of thegeneral formula (R1R2N)nSiH₂, where R1 and R2 are preferablyindependently selected from C1-C4 linear, branched or cyclic carbonchains.[0275] In some embodiments the alkylaminosilane isbis(diethylamino)silane (BDEAS), bis(dimethylamino)silane (BDMAS) ortris(dimethylamino)silane (TriDMAS).

In some embodiments the Si precursor is a silane (silane, disilane,trisilane, trisilylamine) of the general formula (SiH₃)xR where may varyfrom 1 to 4 and wherein R is selected from the comprising H, N, O, CH₂,CH₂—CH₂, SiH₂, SiH, Si with the possible use of a catalyst in ALDregime. Preferably the silane is a C-free silane. Most preferably, thesilane is trisilylamine. In some embodiments a very small amount (<1%)of catalyst may introduced into the reactor. The silanes described abovecan be difficult to use in ALD conditions, as their adsorption on asilicon wafer is not favorable. In some embodiments the use of acatalyst helps the adsorption of silane on the first surface of thesubstrate or the underlying layer. In some embodiments, the introductionof the catalyst is simultaneous with the silane. In some embodiments thecatalyst is an amine or a metal-containing molecule, preferably amolecule containing an early transition metal, most preferably ahafnium-containing molecule, such as Hf(NEt₂)4. In some embodiments, thecatalyst is C-free.

In some embodiments the SiO₂ is deposited using precursors as describedin U.S. Publication No. 2007/0275166 which is hereby incorporated byreference.

In some embodiments the Si precursor used in the selective depositionprocess is an organoaminosilane precursor and it is represented byformula A as follows:

In this class of compounds R and R¹ are selected from the groupconsisting of C₂-C₁₀ alkyl groups, linear, branched, or cyclic,saturated or unsaturated, aromatic, alkylamino groups, heterocyclic,hydrogen, silyl groups, with or without substituents, and R and R¹ alsobeing combinable into a cyclic group. Representative substituents arealkyl groups and particularly the C₁₋₄ alkyl groups, such as ethyl,propyl and butyl, including their isomeric forms, cyclic groups such ascyclopropyl, cyclopentyl, and cyclohexyl. Illustrative of some of thepreferred compounds within this class are represented by the formulas:

where n is 1-6, preferably 4 or 5.

In some embodiments the silicon precursor is an organoaminosilane whichhas two silyl groups pendant from a single nitrogen atom as representedby formula B.

As with the R groups of the Class A compounds, R is selected from thegroup consisting of C₂-C₁₀ alkyl groups, linear, branched, or cyclic,saturated or unsaturated, aromatic, alkylamino groups, and heterocyclic.Specific R groups include methyl, ethyl, propyl, allyl, butyl,dimethylamine group, and cyclic groups such as cyclopropyl, cyclopentyl,and cyclohexyl. Illustrative compounds are represented by the formulas:

It has been found though that even though the above organoaminosilanesare suitable for producing silicon oxide films on a first surface of asubstrate, organoaminosilanes of formula A are preferred.

In some embodiments the silicon precursor can be formed during the ALDtype deposition process. In some embodiments a new vapor phase siliconprecursor is formed which is then also able to adsorb onto a firstsurface of the substrate. This can be referred to as in situ formationof silicon precursors In some embodiments in situ formed siliconprecursors can be a silane compound, for example with the formulaSiL₁L₂L₃L₄, wherein L₁ represents an amino group, such as an alkyl aminogroup and L₂-L₄ represent alkyl or alkoxy group. This silane compound isformed, for example when the first surface of a substrate is contactedwith hexa-alkyldisilazane at 350-450° C. at a pressure of 0.1-50 mbar.

Second Reactants

In some embodiments a second reactant as previously disclosed for use ina GeO₂ selective deposition process can be used with the above mentionedSi precursors. In some embodiments the second reactant is ozone. In someembodiments the second reactant is molecular oxygen. In some embodimentsthe second reactant is one or more of the following compounds:

oxides of nitrogen, such as N₂O, NO and NO₂;

oxyhalide compounds, for example chlorodioxide (ClO₂) and perchloroacid(HClO₄);

peracids, for example perbenzoic acid and peracetic acid;

alcohols, such as methanol and ethanol;

various radicals, for example oxygen radicals (O) or hydroxyl radical(OH); and

hydrogen peroxide (H₂O₂).

In some embodiments the oxygen precursor is not plasma. In someembodiments the oxygen precursor comprises oxygen radicals. As discussedabove, in some embodiments the selective deposition processes disclosedherein do not utilize plasma, such as direct plasma as the direct plasmacan harm the second surface of the substrate. In some instances,however, a selective deposition process could utilize radicals made byplasma as a reactant which are not too energetic, for example oxygenradicals made by plasma that do not destroy or degrade a surface of thesubstrate.

According to some embodiments, at least one compound or the at least oneoxygen containing gas is on the first surface of the substrate prior tocontacting the surface with another compound and/or at least one oxygencontaining gas.

In some embodiments, contacting the substrate surface with each compoundand/or oxygen containing gas is followed by the removal of the compoundand/or oxygen containing gas from the surface of the substrate, forexample by injection of a purge gas, such as an inert gas, into areaction chamber, while in some embodiments contacting the surface ofthe substrate with compounds and/or gas is repeated until the desiredSiO₂ film thickness is obtained. The pressure inside a reaction chambershall be preferably below 100 Torr, more preferably below 2 Torr.Preferably, the H content in the selectively deposited SiO2 film is lessthan 8.1021 atoms/cc.

In some embodiments, an ozone containing gas is a gas mixture comprisingoxygen and ozone with a ratio O₃/O₂ below 30% vol., preferably between5% and 20% vol. Preferably, the oxygen/ozone gas mixture is diluted intoan inert gas, preferably nitrogen.

Selective Deposition of MgO on Dielectric

MgO may be deposited by an atomic layer deposition type process on afirst dielectric surface of a substrate relative to a second surface ofthe same substrate. In some embodiments the dielectric surface is ahydrophilic OH-terminated surface. For example, the dielectric surfacecan be a SiO₂, low-k or GeO₂ surface. In some embodiments the secondsurface may be a conductive surface, a metal surface, or a H-terminatedsurface. The second surface may be, for example, a Cu, Ru, Al, Ni, Co,or other noble metal surface. In some embodiments the second surfacecomprises a metal selected individually from Cu, Ni, Co, Al, Ru andother noble metals. In some embodiments the second surface is a Cusurface. In some embodiments the second surface is a Ni surface. In someembodiments the second surface is a Co surface. In some embodiments thesecond surface is an Al surface. In some embodiments the second surfaceis a Ru surface. In some embodiments the second surface comprises anoble metal. As discussed above, in some embodiments a dielectricsurface may be treated to increase the amount of OH-groups on thesurface.

In some embodiments the conductive surface comprises an oxide such asCuOx, NiOx, CoOx or RuOx or another noble metal oxide. In someembodiments a conductive surface may no longer be conductive after ithas been treated. For example, a conductive surface may be treated priorto or at the beginning of the selective deposition process, such as byoxidation, and the treated surface may no longer be conductive.

In some embodiments the second, metal, surface is purposefully oxidizedwith an oxygen source. In some embodiments the second, metal, surfacehas oxidized in the ambient air and/or contains native oxide. In someembodiments the second, metal, surface contains an oxide which has beendeposited.

In some embodiments MgO deposition on the first surface of the substraterelative to the second surface of the substrate is at least about 90%selective, at least about 95% selective, at least about 96%, 97%, 98% or99% or greater selective. In some embodiments MgO deposition only occurson the first surface and does not occur on the second surface. In someembodiments MgO deposition on the first surface of the substraterelative to the second surface of the substrate is at least about 80%selective, which may be selective enough for some particularapplications. In some embodiments deposition on the first surface of thesubstrate relative to the second surface of the substrate is at leastabout 50% selective, which may be selective enough for some particularapplications.

In some embodiments the MgO is selectively deposited by an ALD typeprocess using, for example, Mg(Cp)₂ as a magnesium reactant and water,ozone or a combination of water and ozone as an oxygen reactant. In someembodiments MgO is selectively deposited by an ALD type process using,for example, Mg(thd)₂ as a Mg reactant and water, ozone, or acombination of water and ozone as an oxygen reactant. Methods fordepositing MgO by ALD are known in the art and can be adapted toselectively deposit MgO on a dielectric surface relative to a metalsurface.

In some embodiments the MgO is deposited by a method as described inPutkonen et al. Enhanced Growth Rate in Atomic Layer Epitaxy Depositionof Magnesium Oxide Thin Films. J. Mater. Chem., 2000. 10:1857-1861,which is hereby incorporated by reference.

As previously discussed, in some embodiments the metal surface may betreated to facilitate selective deposition of MgO on the dielectricsurface relative to the metal surface. In some embodiments, the metalsurface is oxidized prior to deposition in order to facilitate selectivedeposition of MgO on the dielectric surface relative to the metalsurface. In particular in some embodiments a metal surface is oxidizedand MgO is deposited from a magnesium precursor, such as Mg(Cp)₂, andwater. In some embodiments the water in the MgO deposition process mayserve to oxidize the metal surface. Thus, in some embodiments the wateris provided first in the initial ALD cycle, or prior to the first ALDcycle.

In some embodiments a metal surface is oxidized and MgO is depositedfrom a magnesium precursor, such as Mg(Cp)₂, and ozone. In someembodiments the ozone in the MgO deposition process may serve to oxidizethe metal surface. Thus, in some embodiments ozone is provided first inthe initial ALD cycle, or prior to the first ALD cycle.

As previously discussed, in some embodiments the metal surface ispassivated prior to deposition in order to facilitate selectivedeposition of MgO on the dielectric surface relative to the metalsurface. For example, the metal surface can be provided with alkylsilylgroups. In particular in some embodiments a metal surface is passivatedand MgO is deposited from a magnesium precursor, such as Mg(Cp)₂, andwater.

In some embodiments the MgO is deposited by an ALD type process on afirst surface of a substrate. Referring to FIG. 6 and according to apreferred embodiment a substrate comprising a first surface and a secondsurface is provided at step 610 and a dielectric, here MgO, isselectively deposited on a first surface of a substrate by an ALD-typeprocess comprising multiple cycles, each cycle 600 comprising:

contacting the surface of a substrate with a vaporized first precursor,here Mg(Cp)₂, at step 630;

removing excess first precursor and reaction by products, if any, fromthe surface at step 640;

contacting the surface of the substrate with a second vaporizedreactant, here H₂O, at step 650 removing from the surface, at step 660,excess second reactant and any gaseous by-products formed in thereaction between the first precursor layer on the first surface of thesubstrate and the second reactant, and;

repeating, at step 670, the contacting and removing steps until adielectric, here MgO, thin film of the desired thickness has been formedon a first surface of the substrate.

As mentioned above, in some embodiments one or more surfaces of thesubstrate may be treated in order to enhance deposition on one surfacerelative to one or more different surfaces prior to beginning thedeposition process 600. In FIG. 6 this is indicated by step 620 in whichthe second, metal surface is deactivated, such as by passivation oroxidation prior to the deposition of the dielectric, here MgO.

In some embodiments a carrier gas is used in the ALD type depositionprocess, as described above. In some embodiments Mg precursor istransported into a reaction space by a N₂ carrier gas. In someembodiments the N₂ carrier gas flows at a rate of 60 sccm.

In some embodiments, the reactants and reaction by-products can beremoved from the substrate surface by stopping the flow of secondreactant while continuing the flow of an inert carrier gas. In someembodiments the substrate is moved such that different reactantsalternately and sequentially contact the surface of the substrate in adesired sequence for a desired time. In some embodiments the removingsteps, 140 and 160 are not performed. In some embodiments no reactantmay be removed from the various parts of a chamber. In some embodimentsthe substrate is moved from a part of the chamber containing a firstprecursor to another part of the chamber containing the second reactant.In some embodiments the substrate is moved from a first reaction chamberto a second, different reaction chamber.

In some embodiments Mg precursor is heated to 50° C. and transportedthrough heated lines into a reaction space. In some embodiments watervapor is generated in a cylinder kept at 30° C. without the using of anadditional bubbling system. In some embodiments Mg(Cp)₂ is used as a Mgreactant and water, ozone or a combination of water and ozone as anoxygen reactant. In some embodiments the substrate is moved such thatdifferent reactants alternately and sequentially contact the surface ofthe substrate in a desired sequence for a desired time. In someembodiments the substrate is moved from a first reaction chamber to asecond, different reaction chamber. In some embodiments the substrate ismoved within a first reaction chamber.

Selective Deposition of a Pore Sealing Layer

In some embodiments, a GeO₂ layer is selectively deposited as a poresealing layer on a porous, low-k film relative to a metal surface by amethod described herein. In some embodiments, the porous, low-k film andmetal surface may be part of a dual damascene structure. In someembodiments a MgO layer is used as the pore sealing layer and may bedeposited as described herein.

When fabricating integrated circuits, layers of insulating, conductingand semiconducting materials are deposited and patterned to producedesired structures. “Back end” or metallization processes includecontact formation and metal line or wire formation. Contact formationvertically connects conductive layers through an insulating layer.Conventionally, contact vias or openings are formed in the insulatinglayer, which typically comprises a form of oxide such asborophosphosilicate glass (BPSG) or an oxide formed fromtetraethylorthosilicate (TEOS) precursors. The vias are then filled withconductive material, thereby interconnecting electrical devices andwiring above and below the insulating layers. The layers interconnectedby vertical contacts typically include horizontal metal lines runningacross the integrated circuit. Such lines are conventionally formed bydepositing a metal layer over the insulating layer, masking the metallayer in a desired wiring pattern, and etching away metal between thedesired wires or conductive lines.

Damascene processing involves forming trenches in the pattern of thedesired lines, filling or overfilling the trenches with a metal or otherconductive material, and then etching the excess metal back to theinsulating layer. Wires are thus left within the trenches, isolated fromone another in the desired pattern. The etch back process avoids themore difficult photolithographic mask and etching processes ofconventional metal line definition.

In an extension of damascene processing, a process known as dualdamascene involves forming two insulating layers, typically separated byan etch stop material, and forming trenches in the upper insulatinglayer, as described above for damascene processing. After the trencheshave been etched, a further mask is employed to etch contact viasdownwardly through the floor of the trenches and the lower insulatinglayer to expose lower conductive elements where contacts are desired.

More particularly, in some embodiments selective deposition methods areapplied to metallization structures formed in porous “low k” materials.Prior to the highly conformal self-saturating formation of insulationlayers noted above, a sealing layer is first selectively deposited overexposed porous surfaces, blocking the pores. The conformalself-saturating processes cannot then penetrate the pores and the low kdielectric maintains its desired properties. The selective nature of thedeposition process ensures that the deposited sealing layer does notinterfere with the conductive surface at the bottom of the via.

The selective deposition method is selected to block, plug or seal thepores of the porous low k material at the exposed surfaces, withoutfilling the pores to any significant depth into the low k material.Completely filling the pores of the low k material, even with aninsulating material, would negate the advantage of the porous low kmaterial by raising the dielectric constant of the material.

The selective nature of the selective deposition processes disclosedherein enables deposition of a pore sealing layer in a dual damasceneprocess without depositing on the conductive floor of the trenches. Byselectively depositing only on a first, porous low surface relative to asecond, conductive surface on the same substrate there is reduced needto etch downwardly through the floor of the trenches to expose lowerconductive elements. In some embodiments no pore sealing layer isdeposited on a second, conductive surface of the substrate, therebyeliminating the need for an etch to expose the conductive surface. Insome embodiments some amount of pore sealing layer may be deposited onthe second, conductive surface of the substrate, however it can beeasily removed by, for example, an H₂ plasma treatment of the conductivesurface without the need for an additional etch step. In someembodiments the conductive surface is treated prior to beginning thedeposition process. In some embodiments the conductive surface istreated as the beginning of the deposition process. In some embodimentsthe treatment of the conductive surface comprises oxidizing theconductive surface. In some embodiments the conductive surface may nolonger be conductive after it has been treated. For example, theconductive surface may be treated prior to or at the beginning of theselective deposition process, such as by oxidation, and the treatedsurface may no longer be conductive.

In the illustrated embodiment, blocking is accomplished by lining theopening in the porous low k layers 710, 720 with a sealing layer 730 asshown in FIG. 7A while no deposition occurs on the conductive floor ofthe trench, 740. More particularly, the sealing layer 730 is depositedin the opening of the porous low k layer by a method that does not havehigh enough conformality to extensively fill the pores through thethickness of the low k insulators 710, 720. In some embodiments thesealing layer is selectively deposited in the opening of the porous lowk layer relative to the conductive material at the bottom of the via740. Preferably, the selective deposition fills or plugs pores no morethan three pore depths into the low k insulator, where the pore depth isdefined by average pore size, without depositing on the conductivesurfaces of the substrate. More preferably, the selective depositionfails to continuously line pores beyond three pore depths into the low kinsulator. Most preferably, the selective deposition fills pores no morethan one pore depth into the low k material, continuously lines pores nomore than two pore depths into the low k material, and insufficientlylines pores three pore depths into the layer to conduct electricity ifthe deposited material were conductive.

As shown in FIG. 7B, none of the pores are completely filled. The firstpore 760, open to the via 750 (FIG. 7A), is largely filled with thematerial of the sealing layer 730. Due to imperfect conformality,however, the sealing layer 730 has pinched off the opening to the firstpore 760 before complete filling, leaving a void 770 within the firstpore 760. The second pore 762 is shown with a very thin coating 772 ofthe pore walls that can in some instances be continuous. The third pore764 has only non-continuous deposits 774, if any. Similarly, a fourthpore 766, which also represents the third pore depth in terms ofdistance through the pores from the outer (via) surface of the low kmaterial, has only non-continuous deposits 776, if any. In theillustrated embodiment, a fourth pore 768, representing the fourth poredepth from the surface (along different paths), has no appreciabledeposits.

In some embodiments the sealing layer 730 is selectively formed on afirst porous low k surface of a substrate relative to a second,conductive, surface 740 by an ALD type process as described above.Advantageously, a “low conformality” ALD type process for blocking thepores of the low k material can be followed in situ by high conformalityALD layers, having a minimal, uniform thickness to accomplish the goalsof the layers (e.g., adhesion, barrier, electroplating seed layer), thusconserving space for more conductive materials to fill the opening.

In some embodiments the surface of a substrate is alternately andsequentially contacted with the first and second reactants. In someembodiments, the reactants are pulsed into a reaction chamber in aninert carrier gas. In a first step the surface of a substrate iscontacted with a Ge source gas, the surface of the substrate is linedwith the Ge-containing species. In addition, the Ge source gas is ableto penetrate into the porous insulating layer by diffusion. Ifnecessary, the first contacting phase can be lengthened as compared to asubsequent ALD process, ensuring penetration of the metal source gasinto the porous insulating layer.

A number of different Ge precursors can be used in the selective poresealing layer deposition process described herein. Ge precurors asdescribed above for use in GeO₂ selective deposition processes can beused in a selective pore sealing layer deposition process. For example,Ge precursors of the formula (1) through (9) as described above can beused in the selective pore sealing layer deposition process. Asmentioned above, in some embodiments the Ge precursor is Ge(OEt)4 orTDMAGe. In some embodiments, the Ge precursor is Ge(OMe)₄. In someembodiments the Ge-precursor is not a halide. In some embodiments theGe-precursor may comprise a halogen in at least one ligand, but not inall ligands. Preferably the Ge precursor is Ge alkylamide.

Following the first contacting phase, the Ge source gas is removed fromthe surface of the substrate, for example, by being purged from thereaction chamber with a pulse of inert gas. In some embodiments of theinvention, the removal step is insufficient to remove all of the metalsource gas from the pores and some remains trapped in the pores of theinsulating material. The duration of the removal step may be equivalentto that of an ALD process that is optimized to purge reactants from thetrenches and vias, but not optimized to purge out the pores.Alternately, the removal step may be shortened to ensure that metalsource gas remains within the pores of the insulating material.

The surface of a substrate is contacted with a second reactant followingthe removal of the first reactant. Preferably the second reactant is anoxygen source gas. A number of different oxygen sources can be utilized,as outlined above with respect to selective deposition of GeO₂.Preferably the second reactant is H₂O. The second reactant may be anoxygen-containing gas pulse and can be a mixture of oxygen and inactivegas, such as nitrogen or argon. In some embodiments the second reactantmay be a molecular oxygen-containing gas pulse. The preferred oxygencontent of the oxygen-source gas is from about 10% to about 25%. Thus,one source of oxygen may be air. In some embodiments, the secondreactant is molecular oxygen. In some embodiments, the second reactantcomprises an activated or excited oxygen species. In some embodiments,the second reactant comprises ozone. The second reactant may be pureozone or a mixture of ozone, molecular oxygen, and another gas, forexample an inactive gas such as nitrogen or argon. Ozone can be producedby an ozone generator and it is most preferably introduced into thereaction space with the aid of an inert gas of some kind, such asnitrogen, or with the aid of oxygen. In some embodiments, ozone isprovided at a concentration from about 5 vol-% to about 40 vol-%, andpreferably from about 15 vol-% to about 25 vol-%. In other embodiments,the second reactant is oxygen plasma.

The second reactant reacts with the monolayer of Ge-containing speciesselectively adsorbed on the surface of the porous low k material.Additionally, the second reactant diffuses into the insulating materialwhere it reacts with the Ge source gas that remains within the pores.This is a CVD-type reaction, leading to deposition of much more than onemonolayer of GeO₂ within the pores. The second reactant will react withthe first Ge source gas it encounters and thus its diffusion into thepores will be limited, leading to a depletion effect into the insulatinglayer. The result of the depletion effect will be the deposition of themost GeO₂ at the neck of the first pore, with GeO₂ deposition decreasingwith distance into the insulating material. This will narrow the neck ofthe first pore, further limiting diffusion into the porous insulatingmaterial during subsequent ALD cycles. Thus, the alternating processoperates in a selective ALD mode in relatively accessible regions, andin a CVD mode with attending depletion effects in relatively moreconfined regions, such as the pores. From FIGS. 7A and 7B, it will beclear that top surface regions of the first low k material are the mostaccessible regions, a trench or sidewall region of the low k materialhas a reduced accessibility, the accessibility decreasing withincreasing distance to the top surface, and pore regions have the lowestaccessibility. The process can be more generally applied whenever suchdifferences in accessibility exist.

Repetition of the ALD cycle will narrow the neck of the first porefurther by increasing the thickness of the deposited layer and willeventually lead to a continuous, sealing layer blocking off the pores.The combination of the CVD depletion effect and the resulting decreasein diffusion into the pores, will allow this process to seal the porousinsulating material without reducing the insulating properties of thematerial. The number of repetitions needed to seal off the pores willdepend on the pore size and can be determined by the skilled artisanthrough routine experimentation.

As will be appreciated by the skilled artisan in view of the abovedisclosure, this alternating deposition process can be optimized, byproper selection of reactant contact duration and separation (e.g.,removal step duration) for a desired level of conformality. This “lowconformality” modification advantageously achieves a conformality alonga continuum between the near perfectly conformal coverage of a pure ALDprocess (wherein reactant contacting is self-saturating and wellseparated from one another to avoid CVD reactions) and the relativelypoor conformality of a pure CVD process (wherein deposition rates arestrongly influenced by temperature and/or reactant concentration).Advantageously, the skilled artisan can readily tailor the conformalitysuitable for a given geometry and a given purpose for a nonconformallayer through routine experimentation with varied reactant contact stepdurations and separations. It will be appreciated, in view of thedisclosure herein, that selection of contact step durations andseparations can involve one or more of the deposition phases in eachcycle, and that that each cycle can include two, three or more reactantcontacting steps.

Sealing of porous, low-k films is described in U.S. Pat. No. 6,759,325,which is incorporated by reference herein. In particular, pore structureis described and various mechanisms for plugging the pores, such as bydeposition processes, that can be modified to utilize the selective GeO₂deposition processes described herein. For example, ALD processes can bemodified to provide some overlap and thus provide some gas phaseinteractions. In addition, some CVD-like reactions may occur in poresdue to residual reactant that is not removed between provision ofreactants.

In some embodiments the GeO₂ pore sealing layer is deposited on thelow-k film without depositing significant amounts of GeO₂ on a metalsurface, such as a Cu or CuO or oxygen terminated Cu surface, on thebottom of the via. In some embodiments GeO₂ deposition is 90, 95, 95,97, 98, 99% or more selective for the low-k film relative to the metalsurface. In some embodiments, no GeO₂ is formed on the metal surface. Insome embodiments the metal surface remains conductive.

In some embodiments the pore sealing layer is deposited on porous low-kfilm without significantly altering the low-k nature of the film. Forexample, the pore sealing layer may be deposited without significantlyincreasing the effective k-value.

In some embodiments the porous low-k film may be treated to enhanceprecursor adsorption, such as by treatment with N-containing plasma, Nradicals or N atoms.

In some embodiments the sealing layer seals pores of about 3 nmdiameter. In some embodiments the sealing layer seals pores of about 3nm or less diameter. In some embodiments the pore sealing layer is athin GeO₂ layer, for example about 5 nm or less, about 3 nm or less,about 2 nm or less, or even about 1 nm or less.

In some embodiments the pore sealing layer may provide reactive sites,such as OH, for subsequent deposition of a Cu barrier layer by ALD.

Repairing Damaged Dielectric Films and Subsequent Selective Depositionof a Pore Sealing Layer in a Dual Damascene Structure

Some embodiments of the present invention provide a method for repairingprocess-related damage of a dielectric film formed on a substrate causedby processing the dielectric film, wherein the dielectric film has afirst dielectric constant before the processing, and the damageddielectric film has a second dielectric constant which is higher thanthe first dielectric constant, comprising:

(i) adsorbing a first restoration gas containing silicon on a surface ofthe damaged dielectric film by exposing the surface to the first gas torestore the surface with the first gas without depositing a film in theabsence of reactive species, wherein the surface-restored dielectricfilm has a third dielectric constant which is lower than the seconddielectric constant;

(ii) treating the surface with N₂ plasma, and optionally H₂O, andselectively adsorbing a second gas containing Ge on a plasma treatedporous low k surface of the surface-restored dielectric film by exposingthe surface to the second gas, followed by applying a second reactant tothe second gas-adsorbed surface of the dielectric film, to form amonolayer of GeO₂ thereon, wherein the duration of exposing the surfaceto the first gas in step (i) is longer than the duration of exposing thesurface to the second gas in step (ii); and

(iii) repeating step (ii) to selectively deposit monolayer GeO₂ to coverthe surface of the surface-restored dielectric film.

In some embodiments, step (i) corresponds to a restoration step of aporous surface damaged during processes, wherein the first gas isadsorbed on the porous surface. Typically, the damage occurs inside theporous dielectric film, and the first gas (which may be referred to as a“restoration gas”) is required to be diffused and adsorbed through poreshaving a size on the nanometer order. Since the porous surface has alarge surface area and has a low conductance, it takes more time for thegas to reach all the surfaces and be saturated thereon than in the casewhere the gas is adsorbed on a flat surface. Since this process is aself-limiting adsorption reaction process, the number of deposited gasmolecules is determined by the number of reactive surface sites (i.e.,damaged surfaces having OH groups) and is independent of the gasexposure after saturation, and a supply of the gas is such that thereactive surface sites are saturated thereby, and a self-assemblingmonolayer is formed. In some embodiments, the duration of exposure ofthe damaged surface to the first gas (the duration of gas supply) can bedetermined by the degree of damage (e.g., an increase of dielectricconstant by 0.1, 0.2, 0.3, 0.4 as compared with the dielectric constantof the dielectric film prior to the damage), porosity of the film (e.g.,in a range of about 10% to about 60%), flow rate of the first gas (e.g.,in a range of about 0.5 sccm to about 20 sccm), etc., based on routineexperimentations. Typically, the duration of exposure of the damagedsurface to the first gas may be about 2 seconds to about 120 seconds(e.g., including about 3, 5, 10, 20, 40, 80, and values between any twonumbers of the foregoing, typically about 5 seconds or longer).

In some embodiments the restored porous low k surface is then treated byway of exposure to a reactive species. Reactive species are speciesgenerated from a reactant gas by a plasma or other energy. In someembodiments, the reactant gas may be selected from the group consistingof He, Ar, NH₃, H₂, and N₂. Preferably, the reactant gas is N₂, and thereactive species consist of a nitrogen plasma. In some embodiments thereactive species comprises N₂ plasma. In some embodiments the porous lowk surface is treated with reactive species so that the subsequentlyapplied Ge precursor can coordinate with the plasma treated porous low ksurface.

In some embodiments the restored porous low k surface is treated withH₂O after exposure to reactive species in order to form Si—OH sites onthe porous low k surface for subsequent GeO₂ growth.

In some embodiments a GeO₂ sealing layer is selectively deposited by aan ALD type process, as described above, on the porous low k surfacerelative to a second surface of the substrate.

In certain preferred embodiments GeO₂ is selectively deposited on aporous low k surface of a substrate relative to a second, differentsurface of the substrate by an ALD type process, comprising multiplecycles, each cycle comprising alternately and sequentially contactingthe substrate with vapor phase Ge— alkylamide and a second reactantcomprising water. In some embodiments Ge alkylamide is provided as a Geprecursor and is reacted with the first, low k surface. In someembodiments H₂O is then provided as a second reactant to react with theselectively adsorbed Ge precursor to selectively deposit GeO₂.

In some embodiments MgO is selectively deposited as the pore sealinglayer according to the process for MgO selective deposition discussedabove. In some embodiment MgO is deposited from MgCp₂ and water vapor,as MgCp₂ is believed to be non-reactive toward the CuO surface and itreacts with water vapor.

In certain preferred embodiments MgO is selectively deposited on a firstsurface of a substrate relative to a second, different surface of thesubstrate by an ALD type process, comprising multiple cycles, each cyclecomprising alternately and sequentially contacting the substrate withvapor phase Mg(Cp)₂ and a second reactant comprising water.

In some embodiments the second surface is Cu. In some embodiments thesecond surface is CuO. In some embodiments the second, Cu, surface ispurposefully oxidized with an oxygen source to form a CuO surface. Insome embodiments the second, Cu, surface has oxidized in the ambient airand/or contains native oxide. In some embodiments the second, Cu,surface contains an oxide which has been deposited.

As previously discussed, in some embodiments, the Cu surface is oxidizedprior to deposition in order to facilitate selective deposition of GeO₂on the dielectric surface relative to the Cu surface. In someembodiments a second reactant in a selective deposition process mayserve to oxidize the Cu surface. Thus, in some embodiments the secondreactant is provided first in the initial ALD cycle, or prior to thefirst ALD cycle. In some embodiments the Cu surface is oxidized prior tobeginning the selective deposition process.

In some embodiments, during the process flow the Cu surface is keptoxidized as a CuO surface. In some embodiments, after the preferrednumber of deposition cycles have completed the CuO surface can bereduced with H₂ plasma and a Cu barrier can be deposited. In someembodiments, a CuO surface can be reduced with an organic reducing agentsuch as HCOOH, methanol or ethanol or with molecular hydrogen H₂ or withhydrogen containing radicals or hydrogen atoms.

Advantageously, a GeO₂ pore sealing layer, as described herein canprovide good reactive sites (Ge—OH) for instance for ALD barrierdeposition. Additionally, since GeO₂ is selectively deposited usingwater as the second reactant, no further damage to the low-k surface isdone.

The above described ALD type selective deposition process providesconformal growth of the GeO₂ layer, in case the treatment, such astreatment comprising plasma or radicals, can form the reactive sitesalso on the sidewalls. GeO₂ can also provide good reactive sites, in theform of Ge—OH surface terminations, for subsequent ALD barrier layerdeposition. In some embodiments the GeO₂ sealing layer can act as abarrier layer.

In some embodiments a GeO₂ pore sealing layer may be selectivelydeposited on a substrate surface comprising a first, dielectric surfacerelative to a second, Cu surface. The dielectric surface may be a porouslow-k surface, such as a silicon oxide based porous low-k surface. Insome embodiments the Cu surface may be oxidized prior to the beginningof the selective deposition process and may be kept oxidized throughoutthe process. In some embodiments GeO₂ may be selectively deposited froman ALD type process such as a process shown in FIG. 4 comprisingmultiple GeO₂ deposition cycles, each cycle comprising alternately andsequentially contacting the substrate with vapor phase TDMAGe and asecond reactant comprising water.

In some embodiments the GeO₂ selective deposition process can be carriedout at a deposition temperature of 175° C. In some embodiments the firstcontacting step can comprise introducing a vapor phase pulse of TDMAGeinto a reaction chamber. In some embodiments the pulse time is about 3seconds. In some embodiments the removal step may be a purge step.Purging means that vapor phase precursors and/or vapor phase byproductsare removed from the substrate surface such as by evacuating a chamberwith a vacuum pump and/or by replacing the gas inside a reactor with aninert gas such as argon or nitrogen. In some embodiments the firstremoval step can have a purge time of about 6 seconds. In someembodiments the second contacting step comprises contacting thesubstrate with H₂O. In some embodiments the second contacting stepcomprises providing a vapor phase pulse of H₂O into a reaction chamber.In some embodiments the pulse time is about 3 seconds. In someembodiments the second removal step can be a purge step similar to thefirst removal step. In some embodiments the second removal step has apurge time of about 6 seconds.

Example

The selective growth of the GeO₂ pore sealing layer is based, in part,on the lack of growth of GeO₂ deposited from Ge alkylamide and H₂O onCuO (see Table 1, below, for LEIS results). No GeO2 was found on the CuOsurface even after 20 GeO₂ deposition cycles of Ge alkylamide and H₂O.

TABLE 1 Peak areas for Cu, Ge, N, and Co/Ni Cu Ge N Co/Ni Cycles 3keV⁴He⁺ 5 keV²⁰Ne⁺ 3 keV⁴He⁺ 5 keV²⁰Ne⁺ 3 keV⁴He⁺ 5 keV²⁰Ne⁺ 0 184912203 0 0 31 774 1 1554 8959 0 0 68 743 2 1735 10172 0 0 66 729 5 194613902 0 0 61 875 10 1412 10574 0 0 33 812 20 1418 11414 0 0 73 786 501535 6425 607 3758 23 312 250 0 0 1016 7203 0 0

Even if some GeO₂ was deposited on the CuO surface, it most likely canbe removed, since germanium oxide, and especially Ge(II)O is not stableon metal surfaces and can be removed during a H₂ plasma treatment of theCuO surface.

We claim:
 1. A method for selectively depositing a dielectric materialon a dielectric surface of a substrate relative to a metal surface ofthe same substrate, the method comprising: at least one deposition cyclecomprising alternately and sequentially contacting the substrate with aprecursor and a reactant, and wherein the metal surface is treated toinhibit deposition of the dielectric material thereon prior to the atleast one deposition cycle, and wherein the dielectric material isselectively deposited on the dielectric surface relative to the metalsurface with a selectivity of at least 80%.
 2. The method of claim 1,wherein the precursor comprises an aminosilane precursor and thereactant comprises ozone.
 3. The method of claim 1, wherein theprecursor comprises Ge, Sb, Si or Mg.
 4. The method of claim 3, whereinthe precursor comprises a Ge-alkylamine and the reactant is water. 5.The method of claim 3, wherein the precursor comprises Mg(Cp)₂ and thereactant is selected from water, ozone and a combination of water andozone.
 6. The method of claim 1, wherein the dielectric material isselected from GeO₂, SiO₂ and MgO.
 7. The method of claim 1, wherein thedielectric surface comprises a low-k surface.
 8. The method of claim 1,wherein the metal surface comprises Cu.
 9. The method of claim 1,wherein the metal surface is oxidized prior to the at least onedeposition cycle.
 10. The method of claim 1, wherein the dielectricmaterial is selectively deposited on the dielectric surface relative tothe metal surface with a selectivity of at least 90%.
 11. The method ofclaim 1, wherein the selectivity is retained for up to 20 depositioncycles.
 12. A method for selectively depositing a metal on a first metalsurface of a substrate relative to a second, different surface of thesame substrate, the method comprising: treating the second surface toprovide OH, NH_(x), or SH_(x) terminations; and subsequently carryingout at least one deposition cycle comprising alternately andsequentially contacting the substrate with a metal precursor and areactant, wherein the metal is selectively deposited on the firstsurface relative to the second, different surface with a selectivity ofat least 80%.
 13. The method of claim 12, wherein the metal is selectedfrom Sb and Ge.
 14. The method of claim 12, wherein the first metalsurface comprises Ni, Co, Cu, Al or Ru.
 15. The method of claim 12,wherein the second surface is a dielectric surface.
 16. The method ofclaim 12, wherein the metal precursor comprises a Sb reactant having theformula SbX₃, where X is a halogen.
 17. A method for selectivelydepositing a metal or metal oxide material on a first dielectric surfaceof a substrate relative to a second, different surface of the samesubstrate, the method comprising: at least one deposition cyclecomprising alternately and sequentially contacting the substrate with aprecursor comprising a metal and a reactant, and wherein the seconddifferent surface is treated to inhibit deposition of the metal or metaloxide material thereon prior to the at least one deposition cycle, andwherein the metal or metal oxide material is selectively deposited onthe first dielectric surface relative to the second, different surfacewith a selectivity of at least 90%.
 18. The method of claim 17, whereinthe precursor comprises Ni, Fe or Co.
 19. The method of claim 17,wherein the metal or metal oxide is selected from Ni, Fe, Co, Ni oxide,Fe oxide and Co oxide.
 20. The method of claim 17, wherein the firstdielectric surface comprises SiO₂, GeO₂ or a low-k surface.